You may cast 2g. Ultra light weight shallow tuning spool, 3mm deep spool for SLPW 23Millionaire Air, Daiwa 20Alphas Air TW, 21Gekkabijin Air TW, 22Silver Creek Air TW, 20Alphas Air, 19 Steez Air TW. 28mm dia. 3.8g (measured without ball bearing). Spool shaft end has SIC ball to spin fast. Shaft is made of titanium. Fixed brake rotor offer stable brake. Brake is about 35% less than that of stock spool.