Some of the main differences of this extension is the slightly increased diameter of 32.5mm over the standard 31.5 to 32mm to reduce play inside the mast creating point loads and turning the holes 90° so they are length wise in stead of across. With bent aluminium extensions you can clearly see all RDM extensions bend sideways because of a wave hitting the sail. Strength analyses show that by turning the holes 90°, the highest force in the tube (where it will break) is reduced by 47% (1494 MPa against 797 MPa). So that alone makes it 90% stronger, without increasing weight. See pictures of the analyses using finite elements below.
Having the holes side-ways simply creates a massive weak spot. These analyses were done with 6,5mm holes, with bigger holes the difference is even bigger.
Weight: 492 gr
The extensions have a diameter of 32.5 +/-0.1mm to fit the standard internal diameter for RDM masts of 33.0 to 33.2mm, as established by Powerex and No Limitz, the first producers of RDM masts back in 1988. Most brands follow this standard, however it appears some masts have reduced their diameter by a few 0.1mm and may have a tight fit. Also some mast brands have varying diameters within one mast range. Please check your masts diameter before ordering.