You must be logged in and verified to contact the designer.
This is an accessory for the Transformers Generations Titans Return Titan Master Overboard (Overkill) that gives him his G1 Cassette Weapons. The 5mm peg hole is meant to slide over the "weapon handle" on his back in dinosaur mode to recreate his G1 look. This is really meant specifically for the "Overboard" release of this mold, but it is perfectly compatible with any version of this titan master character (i.e. the Crashbash and Clobber re-decos of this same mold).