What's the Minimum Size an Ultrasonic Cleaner for Glasses Should Have?

Many buyers look first at an ultrasonic cleaner's wattage. But for glasses, what matters more is whether the entire pair – opened up, with both temples – fits flat and fully submerged in the tank. If the glasses have to be bent, or stick out above the liquid surface, cavitation won't act evenly across every part.

For most adult glasses (including slightly larger sports and sunglasses), the tank should offer at least around 15 cm of internal length. It also needs enough depth so the temple tips and nose pads are fully submerged too – not just the lenses.

Importantly: length alone says nothing about depth, and therefore nothing about the tank's actual capacity. NURO, for example, offers 600 ml of capacity (up to the MAX line) – it's this combination of length AND volume that ensures even larger glasses are fully submerged.

Stainless steel rather than plastic for the tank (more durable, more hygienic), a timer function for reproducible cleaning times, and sufficient frequency in the 40,000–48,000 Hz range (see What is an ultrasonic cleaner and how does cavitation work?).