Locking carabiner Petzl M33A SL D-shaped aluminium screw-lock, 70 g, 1 pc

Petzl M33A SL is a lightweight, D-shaped aluminium locking carabiner with a screw-lock gate, supplied as a single unit and weighing 70 g. The D profile directs load to the spine for improved strength and controlled alignment with ropes and anchors. The screw-lock mechanism features a visible red indicator when unlocked, allowing the user to confirm gate status at a glance. The body geometry and H cross-section provide a compact connector that is easy to grip, resists abrasion to markings and reduces overall weight while maintaining compatibility with common climbing hardware.

Advantages

The D-shape concentrates forces on the spine for efficient load transfer and predictable behaviour under load. The screw-lock gate gives a simple, reliable locking option suitable for mixed conditions where debris or ice could affect automatic systems. A fluid interior design reduces catch points and helps rotation of attached devices such as pulleys and ascenders. The H cross-section improves handling and preserves surface markings, while the Keylock-style nose minimises involuntary snagging during clipping and unclipping.

Suitable for

• Lead and top-rope climbing where a compact locking connector is needed
• Mountaineering and alpine routes that require lightweight hardware
• Rope access and work-at-height tasks with straightforward screw-lock preference
• Connecting pulleys, ascenders and progress-capture devices with wide cross-sections

Key specifications

• Material: aluminium
• Shape: D-shaped
• Locking system: screw-lock with visual red unlocked indicator
• Weight: 70 g (single piece)
• Cross-section: H-profile for reduced weight and improved grip
• Interior design: smooth profile to limit catch points and facilitate rotation of devices

How to use

Open the gate by rotating the screw sleeve to expose the gate, clip the carabiner to the anchor, rope or device, then screw the sleeve fully down until the red unlocked indicator is no longer visible, confirming the gate is locked. Use the carabiner in orientations that keep the main load on the spine and avoid side loading. Regularly inspect the gate action, screw mechanism and the carabiner body for cracks, deformation or excessive wear before each use.

Usage recommendations

Use the screw-lock Petzl M33A SL where a simple, robust locking method is preferred; avoid locations with repeated side loading or cross-loading. Clean and lubricate the screw sleeve if exposed to salt, mud or ice, and store dry to maintain reliable gate function. Replace the carabiner if any deformation, deep scratches or compromised gate action is detected.