Box Two 24mm External bottom brackets feature cold-forged, CNC-machined alloy cups, dual-labyrinth bearing covers, and precision sealed bearings. They are the perfect match to Box Three, Four cranks, and the ultimate upgrade to the budget BBs sold with most cranksets. Box Two, 24mm External Bottom Brackets, are designed to fit all 24-millimeter crank spindles and frames with 68 or 73 x BC 1.37-inch bottom bracket shells. Features: - Stable Outboard Bearing Position - Precision Abec-5 Sealed Bearings Compatibility: - Compatibility: Box Three, Box Four, Shimano HollowTech II, RaceFace X-Type - Material: 6061-T6 Aluminum - Shell Width: 68mm/73mm - Spindle Type: 24mm - Thread: 1.37 Inch x 24 TPI - Weight: 105 grams / 3.7 ounces Specs: Process: CNC-Machined Cups Material: - Cups: Alloy - Sleeve - ABS Plastic Finish: Anodized Spindle Type: 24mm Shell Width: 68/73mm Thread: 1.37 Inch x 24 TPI (English) Compatibility: - Shell: BSA (Euro) Threaded - Spindle: Box Three, Box Four, Shimano HollowTech II, RaceFace X-Type Weight (+/- 5%): 105 g / 3.7 oz