CMI Ultrascender: The Strongest Ergonomic Ascenders for Rope Access & Climbing
Maximum Strength, Comfort, and Control-One Hand at a Time
From CMI Corporation, the Large Ultrascender sets the benchmark for ascenders with its unmatched 4,600 lbs minimum breaking strength (MBS)-the strongest on the market. Engineered for rope access, rescue, caving, and technical climbing, this ergonomic powerhouse features a molded handgrip for all-day comfort, a thumb notch for effortless cam retraction, and one-handed on/off operation. Compatible with 8.5-16 mm (11/32"-5/8") ropes for vertical or near-vertical ascents, it's built from aircraft-grade aluminum and stainless steel with corrosion-resistant chrome-moly 4140 cams. Available in Red (Right-Hand) and Black (Left-Hand) for singles or pairs-perfect for ambidextrous setups.
Available Configurations
| Configuration |
Hand Orientation |
Color |
Best For |
| Single |
Right-Hand |
Red |
Dominant right-hand users; standard lead ascents |
| Single |
Left-Hand |
Black |
Dominant left-hand users; mirrored rigging |
| Pair |
Left + Right |
Black + Red |
Full-body systems; rescue teams; versatile kits (priced at double single rate) |
Key Features
- Ergonomic Thumb Notch & Molded Grip: Simplifies cam retraction and provides maximum comfort-operates effortlessly with gloves or in wet conditions.
- Ultra-Strong Construction: Chrome-moly 4140 cast steel cams for corrosion resistance and high tensile strength; extruded/machined aircraft aluminum body with stainless steel components.
- One-Handed Operation: Easy on/off rope engagement; safety mechanism prevents accidental release while maximizing control during ascents.
- Broad Rope Compatibility: Fits 8.5-16 mm (11/32"-5/8") diameters-ideal for kernmantle, static, or dynamic lines in vertical hauling.
- Rugged Durability: 4,600 lbs MBS ensures reliability in high-stakes rescue, industrial, or caving scenarios.
- Compact Yet Comfortable: 9.5 oz weight, 3.0" width, and 7.4" height for balanced, lightweight performance without bulk.
Technical Specifications
- Minimum Breaking Strength (MBS): 4,600 lbs (20.9 kN)
- Rope Size: 8.5-16 mm (11/32"-5/8")
- Weight: 9.5 oz (269 g)
- Body Material: Aircraft-grade aluminum & stainless steel
- Cam Material: Cast chrome-moly 4140 steel
- Dimensions: 3.0" W x 7.4" H
- Certifications: Exceeds industry standards for strength and usability
Why Choose CMI Ultrascender?
CMI's Ultrascender isn't just an ascender-it's a workhorse trusted by cavers, rescuers, and rope access pros for its bombproof strength and intuitive design. The ergonomic features reduce hand strain on long hauls, while the pair option enables balanced, two-handed progression for heavier loads or confined spaces. Whether solo climbing or team rigging, it's the obvious choice for gear that lasts and performs under pressure.
Ascend with superior strength, conquer the rope today.
- Using your thumb, open the safety catch and retain it with your middle finger as shown.
- Using your thumb again, open the cam using the thumb natch provided.
- Although it is not necessary for normal use, for convenience the cam can be iocked open by engaging ithe teeth on the cam in the slots on the back of the saiety catch.Advertisements
Make sure the safety catch is fully closed as failure to do so may result in the ascender coming off the rope! Left Hand Version shown, Ultrascenders should be used in pairs.
Care and Maintenance
Carefully clean and dry these ascenders after each use to remove any dirt or foreign material and any moisture. Visually inspect each ascender to check for any visible damage or sharp edges or burrs that may catch the rope. Minor burrs or sharp edges may be smoothed with a fine abrasive cloth before cleaning. Check to insure that the cam and safety mechanisms still move smoothly through their full range of travel. Store these ascenders in a clean, dry place.
Removal From Service
These ascenders should be removed from service if they are dropped from great height, exposed to heat sufficient to alter their surface appearance, or if distortion of any part is apparent, or if the plastic safety trig- ger should be broken, or if the teeth of the cam become worn, or if any cracks are apparent, or if they have any scratches or gouges of more than a superfi- cial nature. If you have any doubts about the integrity and safety of these ascenders, please return them to the manufacturer for inspection and refur- bishment.
