They work really well and most of my axes have wooden masks. The band is inner tube from car or lorry wheels. and these can be easily picked up free from anywhere that changes tyres. Maybe not the most beautiful of items, and I am sure that some of you will come up with more elegant solutions.
Morticing by hand is easy and it does not need to take very long.
So send examples to me that you have made and I will post them up here.