If you're doing mailing, you need tabs. Mailing tabs are required by the US Postal Service for many different types of mailings. Any mail pieces that are folded need to have a tab applied around the open edge to help keep the piece closed during its time in the postal service. Tabbing regulations have changed recently and we have the tabs available to meet those new regulations. Tab size required by the postal service is now 1.5" and depending on the width and thickness of the mailed piece you may need one, two or three tabs along the open edge. Tabbing regulations for booklets have also changed. Booklets above a specific thickness need to have tabs on two or even three edges. Tabbing regulations do change from time to time so in order to be sure that you are able to meet current guidelines you should always check with the regulations of the postal service you are using. For more information on the USPS Tabbing regulations check out the Commercial Letter Tabbing Guidelines
Tabs are required to meet postal guidelines, but what about getting the tabs onto the mailed piece? There are many options available. First of which is a full category of machines called, interestingly enough, tabbers. Tabbers are loaded with a spooled roll of tabs and incorporate a feeder of some sort to pass mailed pieces through the machine and apply tabs as they go. There are two basic styles of tabbers; crash tabbers and inline tabbers. Crash tabbers hold a tab in the path of the piece and the lead edge piece "crashes" into the tab and is then folded around the edge by a pair of tight rollers. Inline tabbers work on a different principal. Inline tabbers fold a tab around the side edge of a mailed piece as it's fed through the machine. Inline tabbers have the benefit of being able to lay multiple tabs on a piece in one pass through the machine. Not only can multiple tabs be laid on the piece in one pass, but those tabs can all be fed off of one continuous roll of spooled tabs. Some crash tabbers can do multiple tabs in one pass but they will have two full spindles that hold individual rolls.