Good!

The woolite Bra Washer Ball is great for machine washing your bras and protecting them from warping. The ball comes with four little soft silicone scrubby balls that help wash the inside of the cups.
The only downfall is this ball only fits up to a C cup. I wear 34D and it just barely squeezes into the ball, mainly cuz of the underwire. The ball would probably be ideal in a frontload washer. As a top load machine does fine, if the machine is large enough. The agitator in the center of the tub could be an obstacle and cause the ball to break from coming in contact with the agitator during washing.
Otherwise this is a great product. I’ve purchased other bra wash balls previously and they broke during the wash cycle. The woolite ball is durable and quality construction and design.