I’ve noticed something about Stern flipper rebuild kits that I’ve purchased on line. The flipper bat will not properly tighten into the plunger. I’ve tried taking pliers to adjust where the plunger squeezes the flipper bat, to no avail. I’ve bought some from a local distributor with no issues. Easy peasy. I even tried these online purchased kits again on other machines to rule out human error and it just won’t tighten enough.