NOTES: The Shalon Chemicals Model No. 4 is perhaps one of the most commonly found surplus gas masks in US. The mask is of simple construction with no inner mask. A five point quick release head harness was used for suspension. The Model No. 4 is a licensed copy of the German Draeger Simplex mask, and was also made in a children's size.

NOTES: This version of the Shalon Chemicals Model No. 4 is identical to the above version, but was made in an extra small size for children. The children's size is quite common, like the adult version.

NOTES: This Israel civilian mask is basically an upgraded Model No. 4. A drinking port was added and an inner mask incorporated to help reduce fogging, a common problem with the Model No. 4. In addition, the inlet/outlet assembly was updated and the head harness was changed from rubber to elastic. All of these changed most likely made the mask for efficient and more comfortable. This updated version is somewhat rare in the US, as fewer were imported.