Hard Hat Suspension Head Protection Suspension Type Ratchet (4-Point) Fits Hat Size One Size Fits Most For Use With Thermalgard(R) Topgard(R) Compatible Hard Hat/Helmet Brand Name MSA SAFETY Compatible Hard Hat/Helmet Grainger Part Number 3RRR5 3RRR6 3RRR7 3RRR9 43FD16 475385 4LP01 4MC41 4MC61 4MC62 4MC63 4MC64 4MC65 4MC66 4MC67 4MD34 4MD36 4MD37 4MD38 4MD39 4MD40 4RB37