The A20S is $112 new and every one I've ever owned developed cracks in the plastic over time. If we're talking about knockoffs, then we shouldn't be using the model number A20S. That model number is reserved for a genuine Schoeps made product.
A Rycote INV-6 is $62 and will last a lifetime. The plastic is more durable and you'll never need to change the elastic. I also don't think it's any bigger than an A20S, but ymmv. I'd take comparison shots, but I no longer own an A20S because they all broke.