In this paper we examine the effect of different brands of highly-coercive permanent magnets on the basic parameters of the leaks protection equipment with the butt-end magnetic coupling (the deviation angle of the coupling halfs, the power loss in a conductive screen, the temperature rise of the screen above the ambient temperature and the required flow rate of coolant water for the screen cooling) while preserving the main indicator - the value of the magnetic coupling transmitting torque. Dimensions of the magnetic coupling when different permanent magnets grades are used remain unchanged.