In essence, a portfolio is simply a more streamlined version of a briefcase. Where a briefcase will usually sport handles and even a shoulder strap in some instances, a portfolio will usually do away with both these amenities. In this way, they are usually held in the hand and transported from place to place while clutched to the breast (or otherwise kept in a larger holdall bag or backpack - keeping in line with modern office-work developments). Another key difference is that a portfolio tends to use a zipper mechanism to keep everything within, whereas a briefcase is likely to use a click mechanism.