This is a question about types of cushion, not a specific product.
Use pillows, foam cushions, booties, or mattress pads to reduce the pressure. Some pads are water- or air-filled to help support and cushion the area. What type of cushion you use depends on your wound and whether you are in bed or in a wheelchair. Talk with your health care provider about what choices would be best for you, including what shapes and types of material.
So there are four categories, two things the choice depends on, and an instruction to decide it with someone who can see the wound. That’s the honest shape of the answer. There’s no single recommended cushion for everyone.
There is one clear “don’t,” and it’s the most useful thing to know if you’re buying something: do not use donut-shaped or ring-shaped cushions. They reduce blood flow to the area, which may cause sores.
That matters because ring cushions are widely sold and the reasoning behind them sounds right. A hole where the sore is seems as though it should take the pressure off the sore. But the effect is on blood flow to the area, and the result can be sores rather than relief.
A cushion is also only half of relieving pressure. The other half is changing position often: about every 2 hours in bed, and every 15 minutes in a wheelchair.