They are different from the ones Ive been using. Old ones had a black plastic casing around it. But these work by putting something under the bottom to lift it.
Narrower than the rps products "best air." 16x25x4 (actual 15 3/4 x24 3/4 x4 1/4, MERV13...HOWEVER, MFGR. RECOMMENDS merv 11 anyway. Just not as tight a fit, but not overly concerned. It should work.