The Delta stem is the first, modern, 31.8 Ø, oversize stem designed specifically for BMX racing. When used with the new BOX Maximus chromoly handlebars (currently the only BMX bars on the market compatible with the Delta), you get the stiffest cockpit available. The added stiffness significantly improves bike handling while putting more upper body power into your pedal stroke and, therefore, forward momentum. Every rider BOX has worked with who has used the Delta/Maximus set-up has noticed a major improvement in stiffness and has been impressed with the more positive pull they get on the bars as they get out of the gate and while cornering and jumping. The stem bodies are extruded and CNC-machined from the highest quality 6061-T6 aluminum. The top clamps are cold forged and CNC-machined for increased stiffness and strength. Delta stems only fit handlebars with 31.8 Ø clamp diameter.