Sliding shower door guides (4)

I have a sling shower door, bottom guides are plastic, install from blelow thd door into a groove in the bottom the door, a small hooked clip tits into the bottom raill of the shower frame and holds shower doors in place.  dont know name of manufacturer, is in a neighborhood of vinyl homes built in 2007 in Avon Indiana, suburb of Indianapolis.  Will need  4 of these guides, looks like they attach behind to screw in the bottom of each frame, seems like they are "springy" and attach on one end to the door. 
 
Do you have any replacements?