These are replacement tubes for the Hear Clear HC206, HCRC and the HCX Hearing Aids and MD Hearing Air models.
There are 2 tubes per package.
The higher the number on the tube, the longer the tubing will be. If you currently have tubes, the size you need will be printed in blue or red on the end where the dome connects. (You may need a magnifying glass and good lighting to see this).