Hand Cranked Simple Marble Machine Kit - Special Occasion, Birthday, Executive Gift This hand-cranked machine is very easy to assemble. Slots and tabs are used in the design to ensure all parts are perfectly aligned. Stainless steel balls are included. See this in action here: https://youtu.be/g-fAkN1YVxc The kit is designed by my friend the talented Michael Henrickson and is manufactured by us in bonnie Scotland. To build this simple kit you just need to add some glue (a PVA type is recommended). The kit is made from laser cut MDF. The build instructions are available to download and read before you purchase the kit from http://www.theywantit.co.uk/SimpleMM.pdf Note - In order to keep postage cost down instruction sheets are not sent out with the kit. This also helps us to save the planet. Note :Contains small parts and is not suitable for children. Thank you for looking