Overview Reviews Product Description C600 series couplings occur in certain niche markets often found on material handling equipment, small tractors, and hydraulic presses.These couplings are machined from solid carbon steel bar stock, are rated to 6000 psi, and feature a leak-free poppet-style valve connection. Greenline Industrial Fitting Catalog New Greenline Industrial Fitting Catalog Product Videos Custom Field Product Reviews Write a Review Write a Review × Greenline 1/4 x 3/8" Series C600 Coupler - Female NPT C601-04-06 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Review Subject * Comments *