I started out using the regular size pads in it AmazonBasics Pet Training and Puppy Pads, Regular - 50-Count , which fit amazing well; however, with Morty's - ahem! - mishaps with aiming, I tried doubling-up on the training pads - would put two of the reg size pads on the holder - and that left just enough pad "hanging" outside of the holder to meet Morty's mishaps in aiming. I was even able to still fasten the holder through the pad, which is awesome!
However, using double to pads to cure Mort's lack of ability to aim for the center every time was costly, so I decided to shop around to see if I could find a solution to our aiming whoes. That's when I stumbled upon these pads at Walmart for just under $10 before tax, but they are available to purchase here at Amazon, Training Pads Extra Large Puppy Pad 26 inch x 30 inch 30 count & it occurred to me that perhaps one XL pad would give Morty that extra allowance he needed, and it could be more affordable to me - it worked! .
These particular pads have been working out wonderfully because I continue to use just one pad and still get the overage protection - I'm pretty sure Morty intentionally pees on the edge sometimes - but since they're quite absorbent, it's very rare that he misses so much that he pees "through the pad." [The time he pees through the pad are the times he literally barely even hits the holder/pad at all because like I said, I'm pretty sure he aims for the edge on purpose most of the time.]
Since Morty is a beagle/dachshund mix, he is a scent hound, which means that I can never just "let him outside" - I always walk him outside with a leash - because scent hounds follow their noses [pretty sure his nose is more Beagle than Dachshund lol]. And with it being extremely hot out now, I allow him to pee indoors at least 50% of the time; I am absolutely thrilled that he has taken to his wee-wee pad like a pro.
All and all I'm very satisfied with this purchase because it has allowed us to have a clearly defined, and mostly contained space within out home for our pup Morty, to go potty in the house, and without ruining our hard floors. Moreover, since the holder itself is plastic, cleaning it up is a breeze! I just spray a bit of Clorox Clean-up on the holder, wipe it and voilà - odor-free home!
As an aside; the holder mentions being skid proof, and though I don't doubt the validity in that claim since the feet, which are on the four corners, do have rubber on the bottom, Morty is still a 7-month-old puppy, and sometimes, he can be a bit ornery and play with his pee-pad - which is always fastened inside the holder. And that subsequently allows him to move the holder from it's original spot because he "pulls" it since he's trying to "pull" the pee-pad off. Also, when my daughter and her friends play fetch with him, sometimes they'll throw his tow toward the same area that his holder sits. When that happens, he tends to run across the pad/pad holder and cause it to move. I'm attaching a video to illustrate what I mean. On this particular day Morty was playing by himself with an empty two liter bottle - he loves bottles! On this occasion, his pad/holder is not in it's normal spot - he's actually moved it into the kitchen. Toward the end you can here him baying out the door at someone/thing. I believe it may have been the neighbor lol :)
But since the times that Morty is able to move the holder are during times in which his doing it intentionally, I still wouldn't dock it for "not" being skid proof because it clearly is. I just wanted to point this out in case you furry family member is anything like mine, and is full of energy - I don't think there much of anything in my house Morty can move when he has high-energy like that. Also in the video, you can see how the XL pads fit onto the regular size holder, and the extra overage it provides - should you have a dog like Morty who needs a little extra overhang because of his aiming woes. I've also included photos of my pup, Morty. He'd climbed up on the chair for no reason really, but it's another example of his high-energy :)