Last updated Jan 30 2024 (c) Herb Johnson The Transit Protector, is a plastic device the size of a 3.5" diskette. Supplied to Apple from Sony, it's yellow plastic, with a thin section of plastic where the heads rest when inserted in the drive. Apple documents I've read, (128K, 512K, 400K and 800K drives) all refer to this device as a "packing disk". They give a part number but it's not upon the device and clearly it's a non-typical Apple part number. Generally they came with external 400K 800K floppy drives or new early Macs. It's hard to determine exactly which Apple products were shipped with it, Apple documents did not always call it out when it was included. I've seen it with 400K Apple drives and 800K external Apple drives. One document with much to say about them is the Apple document for the 800K external disk drive: https://mirrors.apple2.org.za/ftp.apple.asimov.net/documentation/hardware/storage/disks/Apple%203.5%20Disk%20Drive%20Owner%27s%20Guide.pdf Apple 3.5 Disk Drive Owners Guide: 4. [After connecting the drive to your computer,] Turn on the computer's power switch. A yellow plastic packing disk will eject. This disk was inserted at the factory to protect the drive mechanism during shipment. See "Removing a Disk" if the yellow packing disk doesn't eject automatically. You must remove it before you can operate your drive- 5. Gently pull the packing disk all the way out of the drive and keep it for later use. Use this disk to protect your drive mechanism whenever you transport your drive. Removing a disk Before you remove a 3.5 inch disk, make sure the drive's "in use" light is off so you wont lose any data. To remove a disk when yar aomputer is on, push the eject button. Then gently pull the disk out of the slot. The eject button works only when the power is on. When the power ls off: If there is a power failure, or if the e.iect button doesn't release disk, yqt can rernove the disk from the drive manually. To remore a disk manually, use a straightened-out paper dip or similar object. Insert it into the acess hole on the eject buttorL Push hard on the paper clip until the mechanical eject mechanism relased the disk. (if the disk doesnt come out, push harder so you release the spring insid the drive-) Your disks are designed to be easily r emovable. You should not have to use force. If a disk gets stuck, see your dealer. You can lose disk and damage both the disk and the drive mechanism by forcing a disk out. Your drive is making errors. Make sure you have not blocked the air vents or placed the drive on top of the Macintosh where the electromagnetic field will interfere with the drive operation. Caring for your disk drive When you transport the disk drive, insert the yellow packing disk to protect the drive's internal mechanism. (The magnetic heads in the drive have hard ceramic surfaces that could crack if they contact each other.) If you lose the yellow disk, use a blank disk during transport. end of quotes https://downloads.reactivemicro.com/Apple%20II%20Items/Documentation/Manuals/Apple%20Service/Apple%20Technical%20Procedures%20-%20Cross%20Family%20Peripherals%20-%20Vol.%201.pdf Apple Service Technical Procedures (march 1991) Cross Family Products Volume One PN: 072-0230 Drive Mechanism Packaging 1.4 1 Basics When sending in the Apple 3.5 Drive 800K mechanism for exchange, it must be shipped in the Apple-approved packaging, which includes the shipping fixture and the protective packing diskette. Refer to the Illustrated Parts List for additional packaging information. FINISHED-GOODS ASSEMBLY (Figure 1) [parts list and illustration] 003-0003 Packing Disk (for transporting)