Allows adjustment of the Mk23 Hop up, externally, without loosing the slide movement feature. Fits in 2 minutes. Highly Effective.
 
M-TDC is the new design from Hadron Designs, and allows in this form, two possible locations of hop pressure application by clicking out the single adaptor, and rotating 180 degrees.
 
These will require either the;
 
Single Screw Plate
Triple Screw Plate