The PHLster TuckStrut Slotted Spacer is the perfect compliment to the PHLster TuckStrut. Although designed for the requirements of the PHLster Skeleton, they've made sure to address the needs of other manufacturers, focusing on ambidexterity and durability. You'll notice that the slotted spacer is taller than our existing units. When used with the PHLster TuckStrut this is order to keep the short wing of the TuckStrut parallel to the pistol, maintaining stability when worn IWB. We recommend 1-inch screws when using the slotted spacer.