The Amber 19mm American/Mid-size BB is a two-in-one set. If you use the bearings along they fit in a Mid-sized bottom bracket. With the bearing cups provided they fit in an American bottom bracket. You much have a 19mm spindle in either case.
$19.99 @ veinbmx.com – Click to Buy MSRP: $25.99 *Compare & Save $6.00
Bearing Size: Available for 19mm Crank Spindles
Style: Mid Bottom Bracket with Sealed Precision Bearings
Weight: 0 lb 11.7 oz (332 g) Weight includes American Cups.
Miscellaneous: Spindle Spacers, Chainwheel Adapter & American Bottom Bracket included