When choosing an ergonomic chair, you can consider the following factors:

1. Adjustability: Look for a chair that has adjustable features to accommodate different body sizes and postures. This includes adjustments for height, armrest height, and seat and back cushion firmness.

2. Material: Consider the material used to construct the chair. High-quality materials such as breathable mesh or dense foam provide better support and comfort.

3. Seat and back height: Choose a chair with a proper seat and back height for your height. A chair that is too low can cause strain on the lower back, while a chair that is too high can put pressure on the shoulders.

4. Cushion softness: Consider the cushion firmness of the chair. A moderately firm cushion helps provide support while preventing pressure points.

5. Brand and warranty: Finally, it's important to consider the brand and warranty of the chair you're purchasing. Some brands are known for their quality and reliability, while warranties can provide peace of mind in case anything goes wrong with the chair.

When choosing an ergonomic chair, it's recommended to do your research and compare different models and brands to find the one that best suits your needs and budget.