badge has a crown on top with a shield in the middle. slider on back on front reads Federated Malay States V.F. I was wondering if anyone knows much about the badge as I have not found out much about it.
More for users on this SE since OP has not included an image, here's the insignia:
As per comments, VF is Volunteer Force of the Federated Malay States. Principally for foreigners (colonialists), not locals, in four states of what is now Malaysia.