| Name: | DMM Ultra O Durolock |
| Category: | other locking |
| Locking Type: | full-auto |
| Locks: | triple |
| Unlock Style: | twist-lift-countertwist |
| Sleeve Rotation: | 2 x 90° (unlocked) | 2 x 90° (maximum) |
| Shape: | oval |
| Material: | aluminum |
| Profile: | I-Beam |
| Nose: | keylock |
| Rivets: | flush |
| Gate Shield: | full |
| Weight: | 85 g |
| Dimensions: | Length: 109 mm Width: 65.5 mm Gate Opening: 19 mm |
| Strength Ratings: |  25 kN |  12 kN |  7 kN |
| Other Markings: | Forged: DMM A320  | (ratings) WALES UKLaser: A324 EN362:2004/B EN12275Ⓑ CE0598 PAT. 220801474J |  |
| Batch Marking Location: | spine-exterior |
| Msrp: | $33.50 (2022) |
| Collection Criteria: | ★ Mechanically Interesting ★ Demonstrates a Discipline |
| Summary: | dual-sleeve quad action |
| Description & Commentary: | Unique twist-lift-twist-open quadruple-action. The locking mechanism has a strong spring and is extremely secure. Locking oval carabiners are very popular with tree climbers for use with a closed friction hitch or mechanical friction hitch (such as the Akimbo or Rope Runner). The oval shape loads consistently and minimizes crossloading or carabiner rollout - making them ideal for connecting to rigid hardware such as hitch tending pulleys or modern mechanical hitches. They are often attached or detached while on the ground or with two free hands while well secured in the tree. The extra security in this application outweighs the inconvenience of a quadruple-action carabiner. The availability of multi-attachment hitch-tending pulleys such as CMI's RP141 shifted production DRT (MRS) climbing towards more compact carabiners to clean up attachments at the saddle. The parallel side-plates (cheeks) of Treemagineers' Hitch Climber Pulley took up little space on the carabiner, overcoming one of the main disadvantages of oval carabiners and ushering in the modern era of locking ovals. |
| MPN: | A324 |
| Manufacturer Color: | titanium/purple |
| Technical Notice: | Technical Notice |