The Solimould Double has been designed to make 2 knife scales. The cavities are 150x50x25mm. This also means that you can get 2 pen blanks out of each casting if you prefer.
These come with bungs fitted to the bottom to allow de-moulding using an air blower, or alternatively a light tap with a punch through the hole.
We use a dead blow hammer on the back of our moulds to release blanks and this works very well.