* These labels work with any envelope, flat or package, including window envelopes and preprinted bill pay envelopes.

* Postage, mailing and return addresses all print on separate labels.

* When printing labels for use on envelopes (sizes 9-12, Personal, Monarch and Custom Sized), the USPS requires that you use the fluorescent labels supported by Stamps.com.

* When printing labels for use on larger envelopes and packages, you are not required to use fluorescent labels.

* Compatible Dymo models:

Labelwriter: EL40, EL60, Turbo, LW300, LW300 Turbo, LW310, LW320, LW330, LW400, LW400 Turbo, LW Duo, LW Twin Turbo
# CoStar Labelwriter: XL Plus, XL Turbo

* Compatible Seiko models:

SLP Plus, SLP Pro, SLP-EZ 30, SLP120, SLP200, SLP220, SLP240