---
product_id: 73992560
title: "Blue Marble Discover with Dr. Cool Replacement Rock Tumbler Barrel for National Geographic Professional Series Tumbler and Hobby Series Tumblers, 2 Pound Rock Polisher Barrel with Leak-Proof Lid"
brand: "discover with dr. cool"
price: "€ 60.88"
currency: EUR
in_stock: true
reviews_count: 12
category: "Discover With Dr. Cool"
url: https://www.desertcart.hr/products/73992560-blue-marble-discover-with-dr-cool-replacement-rock-tumbler-barrel
store_origin: HR
region: Croatia
---

# Compatible with top National Geographic & Dr. Cool tumblers Quiet, leak-proof rubber barrel 2 lb capacity for pro-level polishing Blue Marble Discover with Dr. Cool Replacement Rock Tumbler Barrel for National Geographic Professional Series Tumbler and Hobby Series Tumblers, 2 Pound Rock Polisher Barrel with Leak-Proof Lid

**Brand:** discover with dr. cool
**Price:** € 60.88
**Availability:** ✅ In Stock

## Summary

> 💎 Elevate your rock polishing game—don’t let grit dull your shine!

## Quick Answers

- **What is this?** Blue Marble Discover with Dr. Cool Replacement Rock Tumbler Barrel for National Geographic Professional Series Tumbler and Hobby Series Tumblers, 2 Pound Rock Polisher Barrel with Leak-Proof Lid by discover with dr. cool
- **How much does it cost?** € 60.88 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/73992560-blue-marble-discover-with-dr-cool-replacement-rock-tumbler-barrel)

## Best For

- discover with dr. cool enthusiasts

## Why This Product

- Trusted discover with dr. cool brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Polish Like a Pro:** Dedicated barrel ensures flawless final polish without grit contamination.
- • **STEM-Approved Quality:** Backed by exceptional service and designed for ages 8+, blending education with hands-on fun.
- • **Expand Your Collection:** Perfect for polishing rocks, gemstones, petrified wood, and sea glass with ease.
- • **Seamless Compatibility:** Fits National Geographic & Discover with Dr. Cool Professional and Hobby Series tumblers effortlessly.
- • **Whisper-Quiet Operation:** Durable rubber construction with leak-proof lid minimizes noise and mess.

## Overview

The Blue Marble Discover with Dr. Cool Replacement Rock Tumbler Barrel is a 2-pound, leak-proof rubber barrel designed for the final polishing stage in rock tumbling. Compatible with National Geographic and Discover with Dr. Cool Professional and Hobby Series tumblers, it ensures quiet operation and prevents grit cross-contamination, delivering a flawless, professional-grade polish for gemstones, rocks, and more.

## Description

Many professional rock enthusiasts keep a dedicated barrel on hand to complete the final stage of polishing because it can be very difficult to make sure that no grit is left behind in your barrel when switching between shaping and polishing steps in the tumbling process. By having an extra barrel, you don't have to worry about rougher grit scuffing up your gemstones while you are trying to get that finished polish.

Review: Works great - I have the grey National Geographic tumbler kit. Came with the small barrel that holds roughly a cup. This one is of the same build and quality. Seems about 3x the size. I don’t think you could go any bigger and still fit on the machine.
Review: great tumbling barrel for smaller tumblers - exactly as advertised

## Features

- POLISHING BARREL – This rock tumbler barrel allows you to polish like a pro. We recommend having a dedicated barrel that is only used for the final step in the polishing process to avoid leaving any remnants of rougher grits that might scratch your gemstones and diminish the final polish.
- REPLACEMENT PART – Barrel is compatible with the National Geographic Professional Rock Tumbler and Hobby Series Tumbler as well as the Discover with Dr. Cool Professional Rock Tumbler and Hobby Series Tumbler.
- QUIET AND CONVENIENT – Constructed of durable rubber and with a leak-proof lid, this barrel is designed to be low-noise and easy to use.
- EXPAND YOUR ROCK COLLECTION – Use this barrel to polish rocks, gemstones, petrified wood, sea glass, and much more.
- HIGH-QUALITY EDUCATIONAL TOYS - We're proud to make the highest quality hands-on science toys, and all our products are backed by exceptional service. If your experience is less than stellar, let us know and we'll make things right!

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B077JGMBJJ |
| Age Range Description | 8 years and up |
| Best Sellers Rank | #45,578 in Arts, Crafts & Sewing ( See Top 100 in Arts, Crafts & Sewing ) #38 in Jewelry Making Polishing & Buffing |
| Brand Name | Discover with Dr. Cool |
| Customer Reviews | 4.6 out of 5 stars 528 Reviews |
| Educational Objective | STEM |
| Included Components | 1 Durable Leak Proof Replacement Barrel |
| Is Assembly Required | No |
| Item Dimensions | 5.5 x 5.5 x 5.5 inches |
| Item Type Name | Rock Tumbler Replacement Barrel |
| Item Weight | 1.39 Pounds |
| Manufacturer | JMW Sales, Inc. |
| Manufacturer Maximum Age (MONTHS) | 1188.00 |
| Manufacturer Minimum Age (MONTHS) | 96.0 |
| Manufacturer Part Number | PROBARREL |
| Material Type | Rubber |
| Model Number | PROBARREL |
| Size | 1 Count (Pack of 1) |
| Sub Brand | Discover with Dr. Cool |
| Theme | Hobbies |
| UPC | 816448023392 |
| Unit Count | 1 Count |

## Product Details

- **Brand:** Discover with Dr. Cool
- **Capacity:** 2 Pounds
- **Color:** Black
- **Material:** Rubber
- **Special Feature:** Leak Proof

## Images

![Blue Marble Discover with Dr. Cool Replacement Rock Tumbler Barrel for National Geographic Professional Series Tumbler and Hobby Series Tumblers, 2 Pound Rock Polisher Barrel with Leak-Proof Lid - Image 1](https://m.media-amazon.com/images/I/51Uj4itNpGL.jpg)

## Questions & Answers

**Q: Is the metal on this barrel stainless steel?**
A: I've been running this barrel for 5 weeks now and seems to be running good. Metal appears to be stainless steel to me since it seems to be heavier than what aluminum would be.

**Q: How to assemble Barrel**
A: It is assembled. Tub and lid. May have to screw on knob to lid.

**Q: where is this made?**
A: Our tumbler barrels are manufactured in China.

**Q: I am looking for a 3 lb barrel for a national geographic rock tumbler.  Fo you have any idea where to find one.**
A: Please contact help@thinkbluemarble.com for parts under warranty.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Works great
*by J***S on February 25, 2025*

I have the grey National Geographic tumbler kit. Came with the small barrel that holds roughly a cup. This one is of the same build and quality. Seems about 3x the size. I don’t think you could go any bigger and still fit on the machine.

### ⭐⭐⭐⭐⭐ great tumbling barrel for smaller tumblers
*by S***R on October 6, 2025*

exactly as advertised

### ⭐⭐⭐⭐⭐ Works well! No leaking!
*by F***4 on June 3, 2025*

So glad I found this! It works perfectly with the Nat Geo rock tumbler.

## Frequently Bought Together

- Discover with Dr. Cool Replacement Rock Tumbler Barrel for National Geographic Professional Series Tumbler and Hobby Series Tumblers, 2 Pound Rock Polisher Barrel with Leak-Proof Lid
- Blue Marble National Geographic Rock Tumbler Grit and Polish Refill Kit - Tumbling Grit Media, Polish Up to 20 lbs. of Rocks, Works with Any Rock Polisher, Rock Tumbler Supplies
- National Geographic Rock Tumbler Kit - 3 Lb. Extra Large Capacity Barrel with 3-Speed Motor & 9-Day Timer, Kit Includes Rocks for Tumbling and Rock Polisher Grit, Rock Tumbler for Adults and Kids

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*Product available on Desertcart Croatia*
*Store origin: HR*
*Last updated: 2026-07-04*