Following in the footsteps of the C-Cup and G-Cup before it, the A-Cup is designed to look and feel like an extension of the camera. It can be used with either eye, providing a comfortable, flexible cushion to push against and a solid third point of contact. It wraps around the eye to block out light, and it doesn't disrupt the camera's shape or balance. Simply put, the A-Cup allows you to comfortably use your camera's EVF, allowing handheld shooting with comfort and ease.
The A-Cup doesn't add a diopter or lens, it simply changes the shape of the EVF's cushion. The A-Cup is compatible with all models in the Sony a7 series.