Most modern horns are known as "double" horns because they are equipped with a "trigger" valve (usually at the thumb) which changes the pitch of the instrument from F to Bb. The Bb side allows more security in the upper register. The trigger also allows the seven lowest notes, C to F below the bass clef staff to be played.

On single hung windows, the top glass is fixed while the bottom glass operates up and down and tilts in for easy cleaning. On double hung windows, both top and bottom sashes operate up and down and also tilt in for easy cleaning.

A single mat is only one mat board that is cut to reveal the artwork. A double mat has both an outer mat and an inner mat. The outer mat shows the most color and is closest to the glass of the frame. The inner mat only shows 1/4 inch frame around the window openings of the mat. Our Frame Kits come with a double mat.

We sell what we in England call a single roll. This is the equivalent to an American double roll. The rolls we sell are 33 feet long and 20.5 inches wide and will cove about 56 square feet.

The vast majority of students here are assigned to standard double rooms. We do, however, have a handful of rooms that are over-sized and designed to accommodate three students. The fee for these rooms is slightly less. These rooms are not double rooms that have been converted to triples to accommodate overcrowded conditions. Single rooms are scarce on the Midtown campus and in several of our Westside buildings.

A single roll of wallpaper covers approximately 27 square feet. A double roll contains twice that amount on one roll. In most cases, wallpaper is sold in double rolls only.

We recommend double loop handles, as poi becomes more secure around two fingers and less likely to come off hands

A single malt is the product of one malt whisky distillery and that one distillery only; it is produced by a complex and cumbersome batch process that makes accountants really squirm. There is no such thing as a double malt unless you are with your rich father-in-law at the bar (technically termed ‘a large one’). Their intensity and complexity of flavours, previously thought to be a handicap to wider sales, are now being sought throughout the world.

The difference relates to the design of the solar tubes. The standard tubes are double-walled, with a vacuum between the two walls of the glass. The centre is filled with air and the heatpipe runs up through the centre. The single walled tube is entirely filled with vacuum, and the vacuum is sealed by a glass-metal weld sealing the heatpipe to the glass. This is technically much more difficult to do, hence the cost is much higher.

Single looped dreads are basically single ended dreads witha loop at the top. Double ended dreads are a lock of synthetic hair with a dread at each end and some undreaded hair in the middle. Basically with double ended dreads you get 2 dreads as opposed to single ended dreads where you get one. As a result, you'll need twice as many single ended looped dreads as double ended dreads, as in the end you'll need about the same number of dreads total for the same coverage.

A single-byte character set is a set of characters or symbols that can be represented with one byte. Most American and European languages use single-byte character sets. A double-byte character set requires two bytes to represent all of the characters. Most East Asian languages (like Chinese or Korean) require double-byte character sets because their alphabet is much larger. Calypso does not support double-byte character sets at this time.

A double room features a large bed suitable for two people to share. A twin room has two separate beds that are suitable for one person in each. A single room has one bed, suitable for one person.

The single shouldered cauls are specifically made for the two caul method. Being flat on one side, they can be used for making "flush cut" (no shoulder) balance rail bushings, as most pianos have, by inserting with the flat side toward the cloth you are installing. Yes. You can use your existing double shouldered cauls as Finals. To convert to the two caul method, just buy the appropriate Intermediate Cauls to go with them. Not exactly.

Single pole thermostats break only one side of the power line to your heater and cannot be turned “off”. Therefore, power is continuous to the heater even if it is not running. The control knob will have a low temperature setting without an “off” position. Double pole thermostats break both sides of the power line; therefore all power to the heater is interrupted. The control knob will have an “off” position.

Single pin lamps are referred to as Slimline fluorescents. Slimline lamps will not operate on Kino Flo HO ballasts. Most double pin (bi-pin) lamps will operate on Kino Flo ballasts. However, Kino Flo HO ballasts will shorten the life span of store bought bi-pin lamps.

Single-action means that the truck, the part of the skate that holds the wheels, has only one cushion, and they are at a 45 degree angle. They allow you to be closer to the floor and give you a feeling of stability when cornering at high speeds. Double-action means that each truck has two cushions and they are at a 10 degree angle. Double-action trucks allow for quicker turns, and make your skates feel much more responsive. Double-action trucks are the most common truck.

Single kayaks provide greater maneuverablity than doubles. Doubles can be faster than singles. Doubles may be able to carry more gear, but keep in mind that they need to carry more than twice as much gear for this to be true. A double will require the use of a rudder to steer. A double on a trip can provide an ill/injured person with a safer place to sit than in a single being towed. Some doubles are more stable than a single but will be more difficult to rescue and pump dry.

Many people prefer to subscribe to this list in "digest" form. This means that all of a day's messages are combined in a single email message with a table of contents. Due to network traffic and other factors, digests aren't received at the same time each day or even at the same time by all subscribers. It's not unusual for digest posts to be separated by more than or less than 24 hours. Occasionally, two digests may arrive on the same day.

In single- or double-blind studies, the participants don't know which medicine is being used, and they can describe what happens without bias. Blind studies are designed to prevent anyone (doctors, nurses, or patients) from influencing the results. This allows scientifically accurate conclusions. In single-blind ("single-masked") studies, only the patient is not told what is being given.