Professional EPDM rubber hose with quick-disconnect couplings designed for connecting Bitmain Antminer Hydro series miners (S19 XP Hydro, S21 Hydro, S21 XP Hydro, S21e XP Hydro and compatible) to your cooling loop.
In Endemine hosting at $0.08/kWh, a typical 3,500 W miner costs about $204/month in power. At home on €0.30/kWh it would be roughly €766/month.