All SM303 have been discontinud here is the replacement E3__N3_-13
Laing SM-303-NHT Series Circulating Pump 1/2" Barb x 1/2" Male Thread 115V

Note: Pump bracket not includid

1-00-0097 Watkins/Hot Spring

Features:

• Low flow provides minimal flow velocities thereby reducing noise.
• Rated for temperatures to 140 degree F and line pressures to 50 PSI
• Requires only 33 watts of power
• 212 degree F dry run cutout provided on pumps standard

Material of Wetted Parts:

• Noryl Housing
• 316 Stainless Steel Rotor and Separating Wall
• Noryl Impeller
• Ceramic Bearing Ball
• Carbon Graphite Bearing Cap
• EPDM O-Ring