I bought this litter box type in hopes it would be the answer to my cat's habit of urinating while standing. Previous litter boxes were way too short (and he would just urinate on the wall behind the box) or they were covered boxes with two separate pieces (in which the urine would run down the horizontal seam between the box and the lid pieces and create a foul odor and more cleaning). Unfortunately, my cat's vertical urination habits could not be overcome with this Modkat box. The liner on the inside also seemed like a great idea at the start but this just created another seam for the urine to run behind. I started to notice the foul ammonia odor again about 5-7 days into installing this box. When I went to tear the box apart, I was frustrated to see that the stray now-rancid smelling urine was just pooling at the bottom of the box, between the liner and outer shell of the box. I replaced the liner with an extra I had bought and even had to replace the charcoal filter because he managed to hit that too.
At this point I was frustrated due to the amount of cost I had sunk into the Modkat and all the other boxes I had tried before this. Now, I have a truly MacGyver'd solution in place in which I have a plastic piece hanging from the ceiling of the box toward the back that does cover the charcoal packet but directs the high-flying urine back down to stay in the tarped area.
The odor has been okay since but I'm sure my cat is bound to find another way around this box's design (like he has on all that came before). At that point, I may have to go out and buy an even taller storage container and borrow a saw to cut a hole in it to make my own box. I was just hoping that the Modkat box would be the more elegant-looking solution to my problem.
Sincerely,
A customer who honestly wished this product had worked out.

I bought the litter box because our older cat now tends to stand while peeing and so was looking for a tall box.
I keep the lid folded back to make room for her head and so far so good.
It really helps to contain the litter too.

I've barely had this set up for a week and my cats love this litter box. I find them using this one more than the ones they are used to (still have out during the transition to modkat). Definitely purchasing more. Also cat that peed over the side is not even an issue anymore. Floor saver!

Best litter box I’ve ever own! Love the replaceable liners!

This litter box has solved our problem of our cat peeing on the back wall of our old litter box and having to clean the floor often as it leaks out. She likes the flip litter box too.