Different button to call different receiver. 

Product description:

APE 350 this five-button bell for guests/chef/kitchen to use and five receivers for waiters to use.

It is a transmitter can be used with 5 receivers.

There are five buttons: Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ

APE6600(Watch Receiver): 

Specifications:2.17*1.77*0.59in(55*45*15mm)

Sound Type: Music/Vibration 

Standby Time:30 days long 

With Pager Quantity:999PCS 

Power Supply: AAA battery 

Call button APE350:

Call distance: 1600ft (open distance), 130-200 ft (indoor)

Power supply: four CR2032 lithium button batteries 

Battery life: about 8-12 months

Specification: 4.45*2.44*0.35 inches(113mm*62mm*9mm)

Weight: 0.15 lb(70g)

Material: ABS carrier and Silica gel button

Surface treatment: spray lacquer

package include

Watch receiver x 5, Call button x 1