Plain Plug Gauge, Size - Go - 8.106mm to 8.110mm & Nogo - 8.290mm to 8.300 mm & Depth Go -16.450mm to 16.523mm, Nogo - 17.041mm to 17.059 mm, Go - Nogo Gauge (Required to check the Barrel plate  Reaming Hole Short Barrel), Code - PPG8.1/17