I recently got the Ultimate Sandbag that Mahler was talking about in an article from a while ago and it’s been great so far. My forearms are sore like they’ve never been sore before and it’s starting to beef up my grip strength. The only problem is that it’s tearing skin off, especially on the first knuckle on my middle fingers. It’s mostly on doing explosive lifts, like high pulls or cleans. I used it again today and just focused on pressing movements, and still managed to tear skin off the two knuckles doing floor presses and military presses.
I also managed to tear skin off on the side of my pinky and first knuckle ring finger prior to this, so it’ll probably be a recurring annoyance unless there’s a way of doing explosive lifts that doesn’t involve tearing up your fingers.