Hello,

I'm sorry for such a dumb question here but I'm having a difficult time finding a galco ankle glove for the 638 j frame (just the j frame size holster) anywhere other than the galco website, specifically been looking at Amazon. I assume the 642, 442 etc. are all the same size holster. Currently all I can find is the 640 which I assume is too large. Thanks.

The J frame Ankle Glove is the same for the .38 and .357 J frames, even though they are not exactly the same overall size firearms. Your only options are left/right hand and retention strap or not.
As far as retailers, just do an internet search for the model numbers AG158 or AG160 (if you're right handed).

Thanks for the response. I'm a police officer and occasionally have to run after people. Is the non thumb break strap retention enough on this holster? Would the back strap option be okay with the shrouded hammer of the 638?

The retention strap goes around the back of the frame, so it will accommodate the 637 638 and 642 the same.
As far as retention, the non thumb break model is very snug fitting, especially at first. I would liken it to level 1 kydex retention. I highly doubt it would come out while running, but maybe during a fight, etc.
If you use a thumb break retention holster for your primary weapon, then I might lean towards that since you have that muscle memory.

I don't have long term experience with J frame ankle carry, although I would recommend carrying something on your other ankle to balance it out.
I really only carry a .380 for ankle carry anymore. It's lighter weight and quieter - no cartridge rattle.