The Erie 129 top is a stainless steel top that mounts to the pump with four small bolts that go up through the top frame and screw into tabs that extend out from the corners of the top. The 129B uses a steel top the fastens down with 4 screws that pass down though the middle of the top to an elevated bracket. The 129B top was used by several companies while the 129 top was used far less. Are you sure you need a 129 top?