Looking for a new chain ring my bike has 40 tooth now but I want to go smaller , just changed my freewheel from 17 to 18, also looking for a 165 mm square crank set

Looking for a new chain ring my bike has 40 tooth now but I want to go smaller , just changed my freewheel from 17 to 18, also looking for a 165 mm square crank set

by a12g28