Wall plug FISCHER DuoHM 4x55 S PH PZ, hollow-wall anchor 8 mm diameter, 55 mm length, Pozidriv screws included

Fischer DuoHM 4x55 S PH PZ is a cavity wall plug designed to fasten fixtures in panel building materials with thicknesses from 9.5 to 30 mm using a single plug length. The combined metal sleeve and nylon base body create a secure anchor: the metal sleeve folds and presses against the back of the panel while the nylon body knots in the material. The set includes four DuoHM 4x55 anchors and four M4 x 55 screws. The plug is grey and intended for use with an 8 mm drill hole and Pozidriv screws.

Advantages

The DuoHM installs quickly and simply with a cordless screwdriver without extra setting tools, reducing installation time by up to 50% compared with conventional panel plugs. Its two-component design (metal sleeve plus nylon body) provides high load capacity while the narrow plug edge keeps the fixing hidden behind the mounted part. The metric internal thread allows the screw to be removed and reinserted multiple times, and the nylon anti-rotation lock protects the panel surface from damage.

Suitable for

• Mounting light to medium loads on hollow panels and composite panel materials
• Applications where a single plug must cover panel thicknesses from 9.5–30 mm
• Quick installation projects using a cordless screwdriver
• Situations requiring repeated screwing and unscrewing of the fastener

When it may not be suitable

The DuoHM is optimised for panel and hollow materials; it is not intended for use in solid masonry, concrete, or heavy‑duty structural applications where heavy anchors or through-bolts are required. For very thin panels below 9.5 mm or panels thicker than 30 mm, a different anchor length or type should be chosen.

Key specifications

• Suitable panel thickness range: 9.5–30 mm
• Anchor diameter (outer): 8 mm
• Overall anchor length: 55 mm
• Recommended drill hole diameter: 8 mm
• Screw type supplied: Pozidriv (PH/PZ), M4 x 55
• Material: nylon body with metal sleeve (two-component technology)

How to use

Drill an 8 mm hole through the panel to the required depth, clean the hole of dust, insert the DuoHM anchor so the narrow plug edge sits flush with the panel surface, and drive in the supplied M4 x 55 Pozidriv screw using a cordless screwdriver. As the screw is tightened, the metal sleeve will fold and press against the rear side of the panel while the nylon body knots in the material, creating a secure fixing. The metric internal thread allows the screw to be removed and reinstalled several times if needed.

What to consider before purchase

• Confirm panel thickness is within 9.5–30 mm range
• Ensure drill bit and screw types match: 8 mm drill hole and Pozidriv drive
• Not suitable for solid masonry or heavy structural loads
• Check that the supplied M4 x 55 screws meet the fixture’s strength requirements

Usage recommendations

Use a cordless screwdriver for fastest installation and avoid using the anchor in solid substrates; for repeated removals, verify thread engagement each time to maintain load performance.