GRK GRK-16219 - RSS™ BLACK STRUCTURAL SCREW 5/16" X 2-3/4"- 100pkRSS screws that are 3 1 8 and longer have CEE Threads which enlarge the screw hole for the non threaded portion of the fastener, allowing the wood to settle easily and increases the screws drawing strength. The CEE Thread also reduces the friction on the screw shank which can result in lowering the driving torque and the likelihood of splitting the wood. This is why the RSS screw is an efficient lag screw alternative. Our round head with built in