nipple shield. help.

are they all pretty much the same? or is one brand better? I was gonna get lansinoh since that is a brand of pump that I will be using, and the brand of bottles and nipples that will be used for the Pumped milk, so I was thinking that the nipple shield would maybe be the same shape as the nipple in the bottle? But I see that Madela has different sizes of nipple shields. lansinoh doesn't. I wanna be prepared snd have one in my hospital bag just in case as the LC only works 3 days so if she isnt there I wanna have some backup plans to try on my own.

please help provide me some info on these :)