STP-15 is Banner Engineering's Specified Test Piece with a 60 mm diameter, designed as a dedicated test artifact for validating safety devices. The unit is 8 inches long, black in color, and weighs about 170 g, with origin listed as China. It is cataloged under Banner part 71931 (alternate designation STP-15) and is described in Banner's literature as a Specified Test Piece for testing safety systems. In practice, STP-15 is used in specified-test-piece procedures to verify the stop/restart behavior of machine guarding systems during trip tests and safety verifications when using Banner's light curtains and related safety products.
