Spank Split Stem - 43mm 31.8 Clamp +/-0 1 1/8" Aluminum BlackSpank Split Stem 43mm 31. 8 Clamp + 0 1 1 8" Aluminum Black. Highly weight optimized single crown stem ideal for Enduro applications with 31. 8mm handlebars Human Factor Design features micro increment size options tuned to fit any rider size and style human. Human Factor cockpit setup index facilitates tuning of upsweep and backsweep Ultra short stack height and true zero degree rise Chamfered barclamp to reduce stress risers and increase fatigue