The upper gets the attention, but the sole decides most of the commercial questions about a slipper.

TPR — the default for indoor

Soft, quiet on hard floors, flexible enough to fold flat for packing. The right answer for the majority of indoor slippers.

Rubber — when grip matters

Harder, heavier and more expensive. Choose it when the slipper will be worn on wet surfaces, or when a tender document asks for a tested anti-slip rating.

EVA and foam — when the slipper is sold on weight

Very light and cheap to ship, which is why bathroom and travel slippers use it. Less durable, and not suitable for institutional laundering.

Fabric — when it is a gift

A fabric sole reads as premium and photographs well, but it will not survive being worn outdoors. Pair it with gift-set packaging, not with a utility listing.