The SK-18AE costs £59.99 and is the wall-mounted option for air-conditioning systems up to 7.5 kW, with an 18 L/h flow figure, 8 m maximum head and noise rated at 18 dB(A) or less. The SK-18CE costs £69.99 and is the corner option for systems up to 8 kW, with a 10 m maximum head, noise rated at 18 dB(A) or less and a confirmed built-in audible overflow warning.
Use those figures as selection boundaries, not promises that ignore the route. Pipe resistance, fittings, access and mounting quality affect the result. For a simple high-wall split, the SK-18AE may be the clearer fit. For a corner position, longer lift requirement or installation where an audible warning is valuable, consider the SK-18CE. Both have a 2-year warranty.