Kel-Tec offers the SUB-SDP, a compact pistol that folds down to 10 inches and includes a brace. The design uses a threaded barrel so a suppressor can attach, and a short Picatinny section can take an optic. The company presents a Defender version in its featured photo and lists further product information on its website.

A commenter reported filing the front sight to clear a rail-mounted laser, noted play between the plastic parts that align the barrel and receiver, and described filling that gap with cured silicone. The same commenter said the gun remains loud with subsonic ammunition even with an R9 can and mentioned a longer homemade baffle stack.