Door/ Window weather strips?

I need a new set of cat whiskers or the weather stripping that goes in the top part of the door for the windows. Browsing Paddock Parts, it looks like there are two different kinds? Is there any difference and if so which ones should I get?

http://www.paddockparts.com/Paddock...alse&mscssid=07855D62FD5AA41C9BFFA4145915AB69

http://www.paddockparts.com/Paddock...alse&mscssid=07855D62FD5AA41C9BFFA4145915AB69

Also how hard are they to take the old ones out and put the new ones in?