This is an accessory for attaching and securing a light to the round part of the fourth photo from the top of the Olympus housing. Insert the red square part in the third photo into the housing and secure it with screws. Then, insert the light into the top part and secure it with the side screw. The light can be up to approximately 2.6 cm in diameter. It is adjustable with the screw. The angle of the light can also be changed. When doing macro photography, your left hand is free, so if there are shakes or undulations, you can firmly grip a rock with your left hand and press the shutter with your right. It is unused but has been stored at home. Please refrain from purchasing if you are concerned.