Black Mountain Exercise Stability Balls | Amazon
Graphic: Erica Offutt

Whether you’re amping up your workout or switching out your office chair, a stability ball will improve your posture and engage your core. You can take your pick between a few different sizes and colors in this sale, all discounted at least $5. Plus, these balls can hold up to 2,000 pounds, which seems like overkill to me, but I guess can’t hurt.

Not sure which size to pick? Check out this chart from the Amazon listing:

45 cm ( under 5' tall).
55 cm (5' to 5'6" tall).
65 cm (5'6" to 6' tall).
75 cm (6' to 6'5" tall).
85 cm (6'5" and over).