m303BÖHLER M303 EXTRA is a corrosion-resistant, martensitic chromium steel with very good toughness, corrosion resistance, good wear resistance and improved machinability and polishability. Compared to 1.2316, BÖHLER M303 EXTRAWhy Choose the M303? Lower Emissions Simplified Installation Minimal Lifecycle Maintenance. Gallery. Description. The M&J Valve Model M-303 is an advanced desn slab gate valve