Black Mountain Pick BMP-LHM Spring Action M/L

It's one of the best thumb picks on the market and adapts really good to all thumbs, is comfortable, solid and works really good, but to me the bumblebee thumb picks are more comfortable and feel more secured in the finger. apart from being shorter and smaller (maybe because I have a small thumb).
You will not go wrong with this one since it adapts to different fingers.

I do not get along with regular thumb picks and usually completely avoid them, but these feel really natural, they feel very securely attached and it's a pleasure to play with them.