This is a simple interface which snaps over a Walthers/Tomytec WBM-L01/WMB-L01 motorised chassis. This then clips into the body of an Oxford Diecast New Routemaster bus with catalogue number NNR001-NNR009. These are 1/148 scale. The bus needs to be dismantled and the designer can provide a .pdf step by step guide to the simple process. There are four interfaces in this product, joined by short sprues which need to be removed before installation.
Link to instructions:-
https://drive.google.com/file/d/1JBvOaT11JpXLpxI08miEKe3RFi8uEs92/view?usp=sharing