This is a modern variant of a classic armrest design; the top is flat with a rounded-off corner on the outside edge. This item is sometimes used for vintage restoration work.
The armrest is fixed on by each of the two leg being trapped against 2 tension hooks (it fits across 4 adjacent hooks). There are two flat fixing bars which pass behind the hooks and each leg of the armrest is fixed to its bar with a fixing screw - the fixings are included with every armrest.
The armrest will then sit reasonably comfortably on top of the tension ring - or a little higher, if preferred, depending on the exact configuration of the tension ring & brackets.
This armrest is designed for 11" diameter banjos (i.e. a 5 ½" radius to the curve) and it is very difficult to fit it to a banjo which has a radius much different from 5 ½".
The dimensions (all approximate) of the armrest are:
180mm long x 25mm wide x 18mm deep except at the fixing points where it is 36mm deep
There are a pair of fixing slots in each leg at approx 37mm centres (for 24 bracket banjos) - filing these out a little will accommodate slightly different spacings. The legs themselves are at approx 75mm centres; as there is often a little bit of "wiggle-room" on tension hooks, this armrest will fit many modern banjos.
The decoration is an embossed pattern made up of lots of tiny "V" shapes and is pretty smooth to the touch; quite comfortable in use.
If you need to work to precise measurements for a particular banjo, please e-mail your requirements - we can sometimes alter an armrest to give different clearances from those given above.