This is our sd2 concave. This concave we can make the following sizes. 7.5 7.6 7.75 7.8 8.0 8.25 8.5 wide. This concave has a steeper tail than the sd3. Rail to rail it is not as steep as the sd3 or sd6. This concave also is not our stock concave we do press it but only on request. We keep the sd3 and sd6 concaves pressed up at all time ready to cut any size custom skateboard you want.