Brand: ATI Performance Products Manufacturer's Part Number: 918997 Part Type: Sockets and Drive Bits Product Line: ATI Harmonic Balancer T-40 Plus Torx Bits Summit Racing Part Number: ATI-918997 UPC: 800157033384 Socket/Bit Style: Hex/Torx Impact Rated: No Number of Pieces Included: 1 Socket/Bit Piece Count: 1 Ratchet Included: No Extensions Included: No Swivel Extension Included: No Socket Material: Steel Socket Finish: Natural Case Included: No Quantity: Sold individually. Socket Drive (application): 1/4 in. Hex/Torx Bit Size: TP-40 Torx Bit Type: Torx plus ATI Harmonic Balancer T-40 Plus Torx Bits ATI dampers are assembled with T-40 Plus countersunk bolts for the strongest possible mechanical connection of the steel assembly to the crankshaft hub. For the racer that is going to service their ATI damper， these ATI harmonic balancer T-40 Plus Torx bits must be used， instead of regular Torx bits for easier removal of the T-40 countersunk bolts. Another bonus of the use of this essential tool is if you run an RCD BAE type gear drive， you can use this Torx bit to remove the idler gear plate to service the gear drive.