EVA wheels

What are EVA wheels? I see that a lot of strollers have them... Are they hollow or solid?

Well, you'd think it was a company or something, but it's not. Here is the scant bit from Wikipedia:

"Ethylene-vinyl acetate is commonly known as acetate or EVA. It is the copolymer of ethylene and vinyl acetate. It is a polymer that approaches elastomeric materials in softness and flexibility, yet can be processed like other thermoplastics. The material has good clarity and gloss, barrier properties, low-temperature toughness, stress-crack resistance, hot-melt adhesive and heat sealing properties and resistance to UV radiation. EVA has little or no odor and is competitive with rubber and vinyl products in many electrical applications."

Also, it's a non-marking substance. The stroller wheels are typically coated in the substance or pure EVA-- so pretty much, we're talking about solid (whether as a coating or pure substance, it's not air-filled).