EYSDON M30*1mm Male to M28.6*0.6mm Female Threads Conversion T Ring Adapter for 1.25 Inch Telescope Filter Converter - AliExpress
M30.3x0.8 female to M28.5x0.6 male thread adapter
TA adapter M28 - M30
M28 x 1.5 Female Radiator Adaptor to Thermostat/Thermostatic Head M30 x 1.5 Male M28-M30 M28F-M30M (BLUMKRAFT) : Amazon.com.be: Tools & Home Improvement
Heimeier Thermostat Adaptor M28 x 1.5 to M30 x 1.5: Heating & Cooling: Amazon.com.au