Heat Treat Foil (321 stainless steel tool wrap) envelopes help lock out the air. This provides surface protection for knives so during the hardening process to prevent decarburization (scale).
***Advised to wear Non-cut Gloves when handling as it can have sharp edges.***
***It will arrive in a cardboard tube for peace of mind that it will be safe during transit and in your workshop***
Another option is Condursal Z1100.