Casio definitely thought about the student/teacher relationship when designing the PX-160. It has a duet play mode, which splits the keyboard into two halves. Each half is the same octave range (about three and a half octaves per side), so a teacher can demonstrate on one side while the student plays on the other at the same pitch. Two headphone jacks allow both players to use headphones without the need for a splitter. If the speakers are being used, they can also be configured to output sound from the left keyboard side to the left speaker and vice versa.
Dual coil "humbucker" pickups, sometimes abbreviated to DC pickups, have two signal-producing coils that are reverse-wound around opposed polarity magnets (similar in principle to the two individual J-pickups or the two halves of a modern Precision pickup, only in a single housing). This significantly reduces unwanted noise from electromagnetic interference compared to single coil pickups. Humbuckers also often produce a higher output level than single coil pickups, though many dual-coil pickups are marketed as retrofits for single-coil designs like the J pickup and advertise a similar output and tonal character to the stock single-coils. Dual coil pickups come in two main varieties; ceramic or ceramic and steel. Ceramic-only magnets have a relatively "harsher" sound than their ceramic and steel counterparts, and are thus used more commonly in heavier rock styles (heavy metal music, hardcore punk, etc.).
No matter which digital piano you choose, you're in for something special. The instruments found on these pages all offer different features, so take a few minutes to think about your needs as a musician and go from there. Whether you go with a higher-end stage piano like the top-selling KAWAI MP11 Professional Piano or a student model Yamaha's NP12 61-Key Entry-Level Piaggero Ultra-Portable Digital Piano, any digital pianos here will enhance your musical journey.