It seems like you’re looking for a 20-teeth gear for a strapping machine. Gears for machinery can vary widely depending on the specifications of the machine they’re intended for. Here’s some guidance on how you might proceed:

1. Consult the Manufacturer: If possible, reach out to the manufacturer of the strapping machine. They should be able to provide you with the exact specifications for the gear you need, including size, material, and any other relevant details.
2. Measurements: If you’re unable to get information from the manufacturer, you’ll need to measure the gear to ensure you get the right replacement. Measure the diameter, pitch, pressure angle, and bore size of the existing gear as accurately as possible.
3. Specialized Suppliers: There are specialized suppliers that deal with gears and other mechanical components. You can search for industrial suppliers or gear manufacturers who might have a 20-teeth gear that fits your requirements.
4. Online Marketplaces: Websites like Alibaba, eBay, or Amazon might have options for gears. Be sure to double-check the specifications and compatibility before making a purchase.
5. Custom Manufacturing: If you can’t find a suitable off-the-shelf replacement, you might need to consider custom manufacturing. Companies that specialize in gear manufacturing can create a gear to your exact specifications.
6. Local Machine Shops: Sometimes local machine shops or engineering workshops can help you fabricate a replacement gear if you bring in the specifications.
7. Online 3D Printing Services: If the gear is not too large or subjected to heavy loads, you might consider 3D printing as an option. There are online services where you can upload your design and have it printed in various materials.

When dealing with machinery components, especially gears, precision and compatibility are crucial for the proper functioning and safety of the equipment. Make sure to double-check all measurements and specifications before making a purchase or fabrication.