The Gerber Chameleon is the only folder I've seen with with the large hole in the pivot area. The only other knives I've seen with the feature are fixed blade neck knives like Fred Perrin's designs and knives like the Emerson LaGriffe, CRKT Bear Claw, and a recent Taylor Cutlery (S&W) model. Gerber also has the River Guide knife with the feature as well.