The original Retroplate™ was designed to replace those truly obsolete, bulky DW Drop and Delta throw-offs. The Drop throw-off never really releases the tension on the snare wires and allows them to slap at the bottom head when released and chokes the snare drum when engaged.
The Delta was designed to replace the Drop and suffers from the exact same deficiencies as the Drop, weighs more, making it essentially a glorified boat anchor.
The DW retrokit™ allows the DW owner to install a low mass, sonically superior Trick throw-off and eliminates the need for a special multi-position butt.