These items are eligible for Lettermail shipping within Canada only (sorry, rest of the world). 

Lettermail shipping items may be combined but adding too many will cause the shipment to be too large/heavy to qualify for Lettermail rates.

You may combine  Lettermail-eligible items with other products in the store; you will be charged the appropriate shipping fee at checkout.

Fine print: Lettermail shipping is offered as a more economical alternative to regular parcel shipping. Lettermail shipments are not insured and cannot be tracked. Please consider your comfort with this risk before selecting Lettermail shipping. Sorry, not all products meet the criteria (weight, thickness) to be eligible for Lettermail shipping.