This Part is a Volute Back with 8 mounts only for a Piranha Bracketless pump only.
This Part is used mostly in Jacuzzi® and Sundance® hot tubs with this specific type of wet end and will not fit others. Note: There are two different versions of this back this one features 8 mounts for the thru bolts the other features 4 mounts. The seals are different by the way for these volutes.. 

Material Type    Plastic
Volute With Seal    No
Manufacturer    Jacuzzi
Model    TheraFlo, TheraMax, Piranha

For other parts related to this part see the list of links below:

201 Seal Pump Parts Kit with Silicon Fits Most Vico Sta-Rite Spa Hot Tub Pumps

(1) Front Bearing & Seal Pump Parts Kit Fits Most Vico Sta-Rite Spa Hot Tub Pumps

(2) Front Bearing & Seal Pump Parts Kit Fits Most Vico Sta-Rite Spa Hot Tub Pumps

Face, Pump, Jacuzzi® or Sundance®, Piranha, Thera-max, Thera-Flo,2"MBT w/ 2 Plugs

Impeller, Piranha, Sundance, Jacuzzi, 2.5HP, Fits some Piranha

O-Ring, 6" ID, 1/8" XSection, Square, Thera-Max, Thera-Flo, Sundance, Jacuzzi, Hotspring

ASP350-6293 Jacuzzi, j premium, j series, j-300,j-310,j-315,j-320,j-325,j-330,j-335,j-340,j-345,j-350,j-355,j-360,j-370,j-380,j-385,j-390,j-395,j-400,j-415,j-425,j-460,j-465,j-470,j-480,j495,j300,j310,j315,j320,j325,j330,j335,j340,j345,j350,j355,j360,j370,j380,j385,j390,j395,j400,j415,j425,j460,j465,j470,j480,j495,6500-287,6500-288,piranha,piranha a, thermax,theraflo,thera-max,thera-flo