Tuner

Round tuning fork. A=440Hz

K&M tuning fork A=440Hz, model 168/2. Rectangular steel

Round tuning fork. A=442Hz

Chromatic tuner from Korg. Suitable for all instruments.

A classic pitch pipe, that allows you to play a specific tone within the chromatic range.
Often used by Barber Shop Quartets. 

Tuner and metronome - two in one!

KORGs clip-on tuner AW-LT100M suitable for most orchestral instruments and easy to clip on.

Professional KORG tuner, model OT-120