What would be a good filler for a heavy bag to really toughen up

HOW TO FILL YOUR MVP LEATHER HEAVY PUNCHING BAG - Nox

How to Fill a Punching Bag: 12 Steps (with Pictures) - wikiHow

I have a WaveMaster heavy bag which would typically be filled with water, I am thinking sand may be a better option long term as water could contaminate, would this affect the effectiveness of the bag? - Quora

Outslayer, Professional Fight Gear

Freestanding Punching Bags: Sand vs. Water vs. Rock

What would be a good filler for a heavy bag to really toughen up my knuckles? Gravel? - Quora

How to Fill a Heavy Bag (the cost effective method) - Whiteknuckle Custom Fight Singapore

I have a WaveMaster heavy bag which would typically be filled with water, I am thinking sand may be a better option long term as water could contaminate, would this affect the

How to Make Your Own Muay Thai Heavy Bag at Home

Punching Bag Filling Options: What's the Best Choice?

I have a WaveMaster heavy bag which would typically be filled with water, I am thinking sand may be a better option long term as water could contaminate, would this affect the

PROLAST Banana Boxing MMA Muay Thai Heavy Punching Bag (choose size) - FIGHT SHOP®

The 6 Best Punching Bags You Can Buy (2024 Update)

Will hitting a heavy bag without wraps, just bare knuckles, toughen up your fists? - Quora