This handguard is a quad rail with picatinny rails on all four sides. This handguard is NOT compatible with M-lok accessories. It will only be compatible with accessories like QD sling mounts that attach to a picatinny rail. Here is a Leapers option that will mount to this handguard:
https://www.opticsplanet.com/leapers-utg-lowpro-picatinny-angled-qd-sling-swivel.html