The Arley Z4 is a slim-profile, hands-free, and wearable breast pump designed for discreet and convenient pumping. Its slim fit ensures comfortable wear under clothing, allowing mothers to pump on the go without being tethered to a traditional pump. The hands-free design enables multitasking while expressing milk. It is likely battery-powered and features adjustable suction levels for personalized comfort. The 'wearable' aspect indicates a design that fits directly into a bra, offering maximum discretion and portability.