The Buffer Kit you will need will also depend on other features of your rifle, such as barrel length and gas system. However, I suggest using the H1 or H2 model of the Aero Precision Enhanced Carbine Buffer Kit at the link below.
https://www.opticsplanet.com/aero-precision-enhanced-carbine-buffer-kit.html?_iv_code=29D-BFA-APAR15ECBK-APRH101242