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Front Rear
Front Rear
Side Top Open for Rigging
Side Top Open for Rigging

Technical Details

I acquired my CMC from Sales Unlimited in 2019.

The CMC is 113 mm. tall, 80 mm. wide, 60 mm. thick, and weighs 236 g.

The frame and cam are milled from aluminum. The rope channel is 14 mm. wide. The frame’s rope channel is square rather than U-shaped, and the cam face is not contoured either. Neither of these aspects hurts the ascenders performance to any significant degree. The inside of the shell has a milled depression that the cam forces the rope into. This spreads the load on the rope, and may increase the holding power of the ascender. It is claimed to help reduce rope damage under shock loading, but I can't confirm this. The top of the rope channel is rounded off so that the rope does not bend over any sharp corners.

The cam has 8 rounded teeth. The cam radius increases from 10 to 38 mm. over an angle of 160°, giving a 25° cam angle. The cam rides axle is a 9.4 mm. (3/8 in.) quick-release pin.

The frame has two holes in the back, drilled from side to side. The lower one is for the keeper cord for the QR pin. The upper one houses a roll pin that retains a wire cable that leaves via another hole drilled through the side of the shell. The other end of the cable enters a hole in the top of the cam, where another pin fitted in a cross hole retains the cable end. This cable acts as a cam keeper, but is also a surprisingly good cam spring. This Rescucender is unlikely to slide down the rope when unweighted.

One side is printed with the CMC logo, "CMC™," "ASCENDER", the UL Classified icon, and a "USA MADE" icon. The other is printes with "UP" in side a filled triangle, a book-with-an-"i" icon. "MEETS NFPA 1983 (2017 ED)," ’Ø11-13mm "T", ’12.5-13mm "G",’ "PART# 341103," and "LOT#19319M041.


The ascender body is milled from an aluminum block, and it is heavier and more rugged than stamped-shell ascenders. It is slightly heavier than the Gibbs, but rugged to extremes. This is extra weight is undesirable for individual cavers, but the bigger-is-better crowd should love the rugged construction.