To wrap up a weatherization project I need to install a chimney top damper in a chimney with a stuck damper. It started as a racoon-proofing job (resident’s neighbor puts out dog food to feed the “cute racoons” ).  Said cute racoons have shimmeyed down other neighbors’ chimneys and trashed houses already—and yes, I’ve already heard the suggestion to trap the raccoons and set them loose in the offendor’s house so he/she can get to know the “cute racoons” better. 

I would install a Lyemance without a cap and screen but due to the critter factor (Lyemances are balanced to lock open and an enterprising racoon can push the flap down) but  I just discovered the Lock Top from Fireplace Technolgies.

Other than price, what is the practical difference between the two models?

What would a chimney sweep prefer to work with? 

Thanks!