T47 Is A Standard Created By Custom Frame Builders. It'S Threaded, Has An Inner Diameter Of 47mm, And Is 73mm Wide. It Has The Design Benefits Of Being Oversized And Wide, But Also The Practical Benefits Of Threads. This Kit Pairs Those Bb'S With 30mm Spindle Cranks. The Cups Have Ceramicspeed Bearings Pressed In. There Are Two Bearing Options. The Standard Bearing Has Ceramicspeed Balls And Hardened-Steel Races. The Coated Bearing Has The Same Balls Running On A 3-Micron Thick Coating Placed On Top Of Those Hardened-Steel Races For Greater Durability And Less Friction Still.In The Box: - 2 Cups With Bearings Installed.- 2 1mm Spacers.- 2 0.5mm Spacers.- 2 Dust Covers.- O-Ring.- Spacer Tube.- All Round Grease.- Sticker Sheet.Technical Data: - With The Benefits Of Both Oversized Shells And The Secure Fit Of Threading, T47 Has The Best Of Both Worlds. These Cups And Bearings Make It Possible To Run Stiff And Light 30mm Spindle Cranks, Like Those From Rotor And Fsa'S 386evo Standard.- Standard Bearings Reduce Drag By 75% Versus Stock Bottom Brackets, Dropping Down To 0.3-0.4 Watts Per Set. This Is The Result Of Hardened-Steel Races Rolling Ceramic Balls That Are 100% Smoother And 15% Harder Than The Ceramic Competition. They Also Last Longer. - Coated Bearings Feature An Even Longer Lifespan And Even Lower Drag. Life Increases By 60% And Drag Drops By 50% Compared To Our Standard. - Applied To The Bearings At The Factory Is All Round Grease. It Can Be Replaced For Lower Drag Race Day Grease, Or Higher Durability Long Life Grease, Which Adds A Bit Of Drag But Stays In When Riding Through Messy Conditions. Maintenance Of Ceramicspeed Bottom Brackets:- We Recommend That You Follow Our Instructions On How To Maintain Your Ceramicspeed Bottom Brackets To Achieve The Lowest Friction And The Best Longevity.