For a 125cc moped, the XL is perfect, very nice and quite ergonomic, and of course non-slip. The only issue is that dirt gets between the holes if you leave it outside, and it's hard to remove

Small for the scooter I bought it for. sym Jet X 125. It keeps the dust in its cells and when you remove it the seat is a mess.
Nice design but that's about it.

I got the 3xl for Piaggio Beverly and secured it with a stapler because otherwise it doesn't fit, it's small. For its price, if it fit, it would be okay, but unfortunately, it's small.

Very good cover!
I have used it on a crypton x for 2 years during the warm months (4-5) months each year and it has done the job it was intended for!

I put it on VF 185 good fit slips a little but it's okay.

For the Honda Dylan 150 2006, I bought the XL size, but maybe I should have gotten the XXL because it has a gap in the back. If it doesn't slip and if it heats up less than before, I will inform you.
**UPDATE
When it rains, make sure to take it off because it gets soaked from underneath as it catches water.
It doesn't actually heat up that much, it slightly slips.

Unfortunately, for the Sym Symphony ST 200 Euro 5, it is not a perfect fit as a glove, as a guy below had written. However, it is not that it doesn't work at all, it just doesn't fully cover the seat. Nevertheless, it is of good quality and aesthetically pleasing.

I got the 3XL for the SYM Symphony ST 200 and it fits perfectly. Both the size of the cover and the straps underneath. It will fit on a slightly wider seat than the SYM, but not on a longer one. In terms of length, it fits just right.

A few specks of dust will definitely gather from the air and it needs to be blown and tapped with hands to clean. Personally, it doesn't bother me enough to take it off and shake it.

The seat no longer gets hot from the sun. Not even in the heat. The girl stopped getting burned when she rides with her swimsuit on, but the material is hard and leaves marks on her when she sits. She prefers it over the hot seat.

I wear the large size on the Ecooter E1S 3000w electric scooter, which is the size of a Vespa. The seat has a glove compartment, the material is of good quality and relatively waterproof, and it definitely does its job as it should. It is definitely worth the money.

I have been really satisfied. I have an Innova i and I bought the XL and it is exactly what I needed. It enhances the saddle and you don't slip at all. Quality product. It is worth every penny and more.

Quality product and aesthetically beautiful.
It truly enhances the saddle while making it more comfortable and flexible.
Size XL is ideal for a Supra, Crypton, etc. type of bike.
In general, the rule is to get a larger size to be sure about the final result.
And this is because on the back side of the cover there are special straps with Velcro that tighten if the cover needs to be secured beyond holding it in place.