Midwest has improved the formulation of the pans. Older trays are thicker and more brittle. The new improved formulated pans are lighter, more flexible and designed to be tougher. If your crate is more than a few months old, it is likely that the replacement pan will be somewhat different from the one you have now. These pans are original Midwest pans - they are redesigned to last longer than the old formulation. Please take care to order the correct size.
If you are still not sure of the crate size, you can find out Midwest Crate you have by measuring the length of the crate. Replacement pans fit crates of sizes 18, 22, 24, 30, 36, 42, and 54".
Simply measure the crate from front to back (the long side) and this will tell you which crate you have. The trays vary by crate model, so it is important that you know the Midwest Crate Series.
For the 24" Folding Crates, the height of the crate is critically important and will determine which pan you need.