The HiperFire Braided Mainspring is a tri-twist, music wire AK mainspring that provides a 2+ pound pull weight, and a hard, positive reset on the popular XAK series triggers. The XAK Mainspring is compatible with HiperFire XAK line of triggers, as well as other stock and aftermarket AK fire controls. Note: Pull weight and feel may vary from receiver-to-receiver, and trigger-to-trigger as there is no "mil-spec" standard for all AK platforms. Stated pull weights are true with the combination of HIPERFIRE XAK triggers and XAK Mainsprings. HiperFire cannot guarantee pull weights in other configurations using triggers or mainsprings from other brands.