The World's NO.1 square spring. The perfect replacement or upgrade for standard mainsprings. 

NO1 FITS - BSA Lightning, Airsporter, Mercury, Supersport, Superstar, Goldstar. Anschutz 335, Original 35, 38, 45, 50, RWS 24, 27, 34, 45, 50 Relum. Air Arms (all models).  HW50, HW55, HW85, HW95, HW98, HW99, Haenel, Lion, ASI CF 16/20, Webley Mk3 (if the spring guide is reduced by 20 thou)

NO2 FITS - BSA Meteor, Milbro Diana G80 and 27, Norica, Baikal, Cometa 300/400 plus 5, 50, 100, 220 with coils removed, Most SMK models. 

NO3 FITS - BSA Superstar (12ftlbs only), Webley (all models except Eclipse and MK3), Remington Express. 

NO4 FITS - HW35 (Diana Orig RWS 52, 48, 54)

NO5 FITS - HW80, Webley Eclipse

NO6 FITS - HW77, HW97, Feinwerkbau Sport, also larger original models if ultimate power required

NO7 FITS - ASI Sniper, Magnum (and all other ASI models)