2" BSPT Male Square Head Plug 316 - SP-2 Technical data is applicable to the full range of 316 Stainless Steel Adaptors only. Threads: Tapered in conformity with ISO 7.1, BS 21, DIN?2999. Parallel in conformity with BS 2779, ISO 228. Dimensions: All components are manufactured to the requirements of ASTM A-351. The dimensions are in accordance with ANSI B16.3.