Yeah or nay? I've always had scrawny forearms, and in the past if I added in extra wrist curls I'd often end up with tendonitis at the elbow (Golfer's elbow).

Have been thinking about getting a set, but not sure if I'm just going to end up giving myself tendonitis again, or if it works a little differently than wrist curls.

I used them for about 6 months and found that while it trained my grip decently, it wasn't as effective as doing things like farmers carries, dumbbell shrugs, or deadlifts with double over grip. Honestly, it was a huge hassle to carry them around the gym and not lose them. I can't speak to tendonitis but I imagine it wouldn't be a problem because it trains the forearms through grip strength instead of wrist motion.

I have some but I don't think they are all that effective. I would say doing farmer carries with kettlebells is the best thing. Grab one or two and just walk until you can't hold it anymore, rest and repeat.

Don't do wrist curls is my advice. I've never found them effective at really growing your wrists that much if at all but instead puts major strain on the wrist and forearm.

I echo the farmers carries for grip strength. Make sure you have a tight hold on the dumbbell or kettlebell. Heavy for shorter distance or time (like super heavy for 10 sec or to a point of reference, heavy for 15-20 sec or further out etc) and lighter for longer distance or time (up the street, stop rest and back or for 45 sec to a min).

Honestly, forearms are like calves. They can be grown some and become stronger, but size is limited genetically to an extent. I have skinny forearms and wrists but doing a lot of carries and deadlifts with double over grip as opposed to having one arm pronated and the other supinated, and using a hook grip with fingers over thumb, have made my wrists very strong and limited elbow tendon issues greatly.

One other note, if you are doing squats often, make sure on back loaded squats that your wrists aren't cocked severely and relatively straight in relation to the rest of your forearm. A lot of elbow issues actually originate when a trainee improperly hold the barbell behind him or her. Be aware of your wrist position and if you can feel or see that your hand is at almost a 90 degree angle to your forearm, make sure you place your thumb over the bar and straighten out the wrist. Also, keep the elbows tight and closer to the body and not flaired out. This can eliminate a good deal of elbow issues that many commonly associate with presses when its actually the squat thaqt caused the elbow issue. Happens a lot in strength training.