Coaxial cavity filter around 85 MHz, could be chopped to 2m or 70cm i have a number of these may even have 4 very l similar if you wanted to make a duplexe,r first in first served there .. the photo is a generic one so the photo will look a bit like this one however RF connectors and colour may be different. suggest if you are going to use them at 70 cm cut it down to a 2 meter frequency cavity and operate it at 3/4 wavelength......better performance , higher "Q" and make pick up loops 70 cm size.

these are a cheap price for a cavity filter with invar temp compensation, made by a reputable RF company

you could never make one for $50