43 x 43mm drop-in bottom fitting. Allows quickly attach and detach your camera from the tripod | UNC 1/4-20 interface, made of ABS Resin, Lightweight and durable | Matte surface of non-slip design, with cameras on will not twist, 6.6lb load capacity | Little black spring loaded pin double prevents cameras on from twist | Compatible with Sony D680 580 VCT-580RM, VCT-680RM, VCT-50AV, VCT-60AV, VCT-80AV, VCT-R640, VPR1; For Somita ST-3540 /666 3520 3560, for Velbon CX-444, CX-888, CX-460, CX-460mini, CX-470, CX-570, CX-690, DF-50 (more models see in below descriptions)