TT: Toptube; DT: Downtube; ø: Symbol indicating diameter, you could also describe it as the internal width of a tube; SS: Seattube; MidsizeBB: A bottom bracket where USA style bearings fit/press directly into the frame (this is not the same as Spanish or Euro); Lasercut: Where parts have been accurately cut using a laser instead of the cheaper option of being stamped out; Heat-treated: A process of adding heat to improve strength; Magma Heat-Treatment: This is our term for our full post welding heat treatment process;4130: A type of Cromoly used predominately on quality bmx bikes, 20‘‘: The ‘‘ indicated Inches, an older but still common Imperial measuring system; lbs: The abreviation for weight in pounds; oz: The abreviation for weight in Ounces; butted: When a tube varies in thickness to save weight and add strength; Loose bearing: Used when the bearings are unsealed; Euro BB: A common MTB/race bottom bracket size now also used on bmxs where the bearings+case are threaded into the frame; USA BB: the more common and larger bottom bracket used on the majority of all bmx bikes up until 2003; Spanish BB: A much smaller version of the Midsize BB where the bearing press directly into the frame, only really suitable for flatland.