I dont see many options. they all appear similar to my eye. I have avoided them as I'm okay with two hand opening since I have two hands.
I do like factory ones though such as the lochsa and others made by Buck. I like thumb studs and one handed openers in general and on a 110. these add ons im not sure how durable they are?
I have a JAG custom with one and so far its been good on opening. its larger and visually odd a bit but I dont mind it as it works. it has texturing and is mirrored in the pic on the blade. appears as scratches but it is just a mirror image. this i kinda like as I use it to hold my thumb still on using.
the smaller ones are visually more appealing to me, but the one I got works so I'm good with it.
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