Series 518 Surface Mount Open Frame Collet Sockets. Open frame allows for more efficient utilization of board space and better cooling. Compatible with automatic insertion equipment. Side-to-side and end-to-end stackable. Body material is black UL 94V-0 Glass-Filled 4/6 Nylon Pin body is Brass Alloy 360 1/2 hard per UNS C36000 ASTMB16-000 4-fingered collet contact is Beryllium Copper Alloy per UNS C17200 ASTM-B194-01. Insertion Force:180 grams/pin; Withdrawal Force:90 grams/pin; Normal Force:140 grams/pin; based on a .018 [.46] diameter test lead. Accepts leads .015-.025 mm diameter, 2.54-3.18 mm long. Suggested PCB pad size:1.60 mm diameter