From the outside they are almost identacle. But on the inside is where they are really different.

The SST is a conventional boat tail bullet with a plastic tip. The jacket is relatively thin and gradually thickens toward its base. It is not bonded in any way and at higher velocities the jacket and core can seaperate.

The interbond is a chemically bonded bullet with a plastic tip. The jacket starts out thin in order to initiate expansion then rapidly thickens to control the depth of expansion. The jacket is bonded to the lead core and even at very high velocities the jacket will remain intact with the core and will retain far more weight thanthe SST.

Here are the two side by side so you can get a look at the differances. The SST is on the right and the interbond on the left.