What is this called and can I buy a replacement? Kwikset door handle set : Locksmith

My front door handle was loose and while trying to tighten I realized the inside screws were loose. I ended up taking off the entire thing and re-tightening (thanks YouTube for the diy) but have managed to strip the hex screw that tightens the handle. Can I buy a replacement of just the insert shown here? If so, what is it called and where?

Thank you!!!

Source link

Call Now ButtonCall Now!