Official YS-110 specifications:

Guide number in air:  22

Color temp: 5400K, 5100K with diffuser

Coverage: 105 degrees (with diffuser)

Recycle time: 3 seconds

Depth rating: 196ft (60 meters)

13 Manual settings

Fired by sync cable or fiber optic cable

Weight in water: slightly negative

The YS-110 is a solid, popular mid-range strobe used by high-end compact camera underwater photographers, and dSLR underwater photographers. I've used it extensively for macro and wide-angle and it works well and is reliable. It's fairly small, light, and slightly negative underwater which is very nice.

You should also consider reading our YS-D1 strobe review, which is a much more recent strobe.

YS-110 Pros

• Reliable, readily available, good size and weight, good price point. Easily serviced or replaced around the world.

• Good build quality, good angle of coverage

• Uses 4 AA batteries. Batteries usually will last for 3 dives of heavy shooting.

• Works great with my Sea & Sea TTL-converter III for nikon, for macro & close focus wide angle.

• Good range of manual settings.

• It has a high-intensity focus light

YS-110 Cons

• The strobe could be a little stronger, and have a warmer color temp for wide-angle, but couldn't most strobes be stronger? 

• Diffusers are a little too strong and easy to lose

YS-110 settings and configuration

Set the main dial to TTL when using a TTL converter

Manual 1 - used with fiber-optic cable and cameras with a pre-flash 

Manual 2  - used with fiber-optic cable and cameras without a pre-flash

Manual 1 or Manual 2 can be used when using a camera with a sync cord connection.

The slave button should be "off", unless you are using a fiber optic cable and slaving the strobe off a camera pre-flash.

The power setting dial should be fairly obvious how to use, "full" is full power and "min" is the minimum power setting.

Comparison between other strobes:

The Ikelite DS160 is more expensive, heavier, recycles faster, and is a warmer strobe.

Here I compare it with the Inon Z240 strobe.

Price

This strobe was replaced by the YS-110a, which recycles faster and has better support for compact cameras and optical TTL. Used YS-110's can go for $275-$430.

Further Reading

Underwater Strobe Guide