LaRue Tactical SPR/M4 1.93in Mount QD 30mm Black. 5 mount (LT104) except it is 1.93" above the rail in order to get riflescopes (like the S&B ShortDot) up above top-mounted laser/illuminators like PEQ-2's and PEQ-15's... It is as simple as that. If you do NOT need the clearance over a laser/illuminator order the LT104. The LT135 places the centerline of the optic 1.93" above the top of the rail. The extended cantilever positions the scope far out front over the handguard eliminating the need to span from the receiver to the handguard. The popularity of the SPR series of mounts is partially due to the innovative backbone that connects the split vertical rings. This design provides a more robust platform for the optics increases repeatability and eliminates the need for time-consuming lapping. The rings are precision-machined with the tightest tolerances and feature threaded steel inserts built to withstand a lifetime of abuse. Like all LaRue mounts it is precision-machined out of bar-stock aluminum and matt black anodized to provide a durable non-reflective surface finish. The locking LaRue Speed Levers provide outstanding return to zero; the optic can be removed and replaced without loss of zero. Guaranteed. Assembly and adjustment only takes a few minutes then off to the range. Specifications for LaRue Tactical SPR/M4 1.93in Mount QD: Manufacturer: LaRue Tactical Color: Black Condition: New Last Chance: Yes Package Contents: LaRue Tactical SPR/M4 1.93in Mount QD LaRue Tactical LT135-30: SPR/M4 1.93in Mount QD 30mm Black