Desk Chair Cushion Soft Seat Cushion with Removable Cover, Office Chair Cushion Seat Cushion with Back Support Rocking Chair Cushion.It is made of a soft material.

• Comfort and Support: Filled with high-elastic PP cotton or polyester fiber, the cushion is thick, warm, and comfortable, designed for sitting for a long time without burden.
• Ergonomic Design: It disperses pressure on the buttocks and reduces strain on the waist and hips, protecting them from collapsing and helping maintain proper posture.
• Durable and Easy to Maintain: The cushion is anti-deformation and durable for long-term use. Many designs feature a zipper for a removable and washable cover (hand or machine wash).
• Non-Slip Feature: It typically includes ties and an adjustable back strap or non-slip silicone particles on the reverse side to ensure it stays securely in place on the chair.
• Versatility: Suitable for a variety of chairs, including office chairs, dining chairs, computer chairs, and rocking chairs. It can also be used as a sofa cover or floor cushion. 

Actual sizes

• Approximately 90 x 50 cm (35.4 x 19.7 inches)
• Approximately 100 x 46 cm (39 x 18 inches)
• Other, smaller square versions can be around 40 x 40 cm (16 x 16 inches) or 45 x 45 cm (18 x 18 inches).