UPVC Screws. Maco Offset Upvc Window Lock Rods 25mm Backset GR1 GR2 GR3 GR4. Backset: 25mm. Gearbox Mounted: Offset : Overall length = 60mm : Overall thickness is 6mm. The new lock cams have a Allen key hole in them which when you turn it will move the cams in and out approx 1-2mm to adjust the window compression.
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