Type FP28 glazing packers are great at helping you install window or glass fixtures. These 1000 plastic window glazing packers can help make your installation safer and ensure that the glass unit does not deflect from its frame. During a window installation, it’s very important to make sure that your unit is positioned correctly. The Type FP28 glazing packers can help you ensure that your unit is plumb to its frame and is in the exact position that you want it to be.