I have a like/dislike relationship with mine. I do think there is only one size.
Likes - zipper pockets, ability to vary the weights, velcro 'buckle'. If adding more weights you do have to 'stuff' it
Dislikes - seem too loose overall. They have to be a bit loose to fit over my weight gloves (they are open on the inside so no protection which is OK). But they just don't fit snug on me and it bothers me a bit. They only come with 2x 0.5lb weights per glove.
Options
A) I have 2lb fixed weight gloves that fit much better. So I use them when I'm going to use 2lb consistently. But they're a bit tough for uncoordinated me to get on during the quick changes. And the 2lb is fixed. I've had them awhile and use them for kickboxing
B) 1lb wrist bands. These just slip over my hand and are quick and easy. It weights at the wrist though and not on the hand. OK for most things. These are quite old and I don't remember where they came from.
C) Sinkers (someone's bright idea on these forums, sorry don't remember who but there is a thread) to add weights into the zipper pockets. I found some nice, heavy round ones at Sports Authority. They fit into the pockets. It looks kinda bulky, but
I have a little basket with all my toys for quick and easy access