We recently upgraded the tuning lugs, flesh hoops and skins on these oak Gon Bops bongos, and did a bit of shell repair. The tuning lugs are custom formed from 5/16″ 304 stainless steel, and guaranteed for life. The flesh hoops are 3/16″ round 304 stainless steel. The skins are steer- 1mm on the macho, 1.6mm on the hembra.