Simple to Install: fit the screw threads perfectly. It fastened the gear hub cap securely in place, The spring wound on easily and not your dough hook and other attachments stay in place with good pressure instead of bouncing around with heavy ingredients Must Have Attachment: These springs and washers are a must to keep the attachments tight and ensure there is no wobble while mixing, have value when adding to your new mixer Useful Replacement: This has been very helpful in keeping different attachments from falling off of your mixer Mixer parts accessories and replacement