Clark Masts new MT series of portable masts offers a 4" base tube and a compact retracted to extended height ratio. The Clark Masts MT portable masts low retracted height results in the use of a strong 1.5" or 2" diameter top section.    
The Clark Masts MT portable mast series heavy duty construction and, especially their heavy duty locking collars, provide for vertical headload capabilities from 10 to 20 Kg. 

Extended heights of from 6 to 16 metres make the MT series portable masts especially suited to the rigors of lighting and other applications where medium duty directional headloads are required to be lifted by cost effective, rapidly deployed air-operated portable masts.

The Clark Masts MT portable mast series is available in locking clamp collar variant only.

Shown above is a Clark Masts model MT6-5, 6 metre mast with a 20 Kg headload capability.

The Clark QTM portable lightweight air-operated telescopic mast series was first introduced back in 1959 (Australia saw it in the early 1960's courtesy of a company called Belling-Lee and the foresight of a gentleman working for them at the time, Frank Welsh). In 1959, father of the Clark Mast, Alec Clark (who has only just recently retired from the company) foresaw the need, in addition to their 1957 introduced PT Series, for an easily handled lightweight portable mast and designed the QTM Series.
 
Today Clark Masts two portable mast range has become eighteen, including the new heavier duty MT Series shown on this page. 

The distinguishing feature of nearly all Clark Masts portable telescopic masts, including the MT portable mast series, are their air-operation and portability. This method of extension makes the mast self contained, lightweight, easy and rapid to extend and very gentle in retraction. Heavy duty Locking Collars on each Clark Masts MT portable mast section allow sections to be locked together at any extension height, making the mast usable over a variable height range or alternatively locked at maximum height for long periods of time when the air supply may be removed. All Clark Masts MT series portable masts have the advantage of allowing the headload to be easily turned after the collars have been locked.

Clark Masts MT series portable masts are used for lifting, from 6 to 16 metres, medium weight (up to 20 Kg) , lights, antennas, video and still cameras, sound measurement, air pollution monitoring equipment and a great deal of other apparatus which has directional and/or medium lift requirements. Clark Masts MT Series portable masts may be used un-guyed or guyed depending on the model and wind conditions. Clark Masts MT portable masts are supplied with three way guy collars already fixed at the most appropriate height. All MT portable masts are rated at a wind speed of 128 Km/hr when guyed. A 24 mm Clamp Collar Socket, that tightly clamps the spigot of the headload to the mast and releases instantly when required, is fitted to all MT series portable masts.

There is also a full range of Clark Masts MT portable mast accessories available through Australian Distributor Portable Masts Australia Pty Ltd, including guy assemblies & guy pickets for use in strong winds, weather covers and vehicle mounting and shelter attachment brackets. Clark Masts MT series telescopic masts may be extended using a variety of air sources. For example Clark Masts have available 12 and 24 volt DC as well as 230 volt AC operated Air Source/Mast Control units, handpumps, as well as adaptors for allowing the use of a truck's air supply. Details on alternate air supply equipment may be found here.

Below are shown Clark Masts MT series portable mast specifications. Masts with extended heights from 6 to 16 metres are available in the MT series for use in applications from emergency portable lighting (see Clark's Teklite Masts where specialist Emergency Portable Lighting Masts are required) to portable communications and aerial photography.

Mast Collar and Base
Options

Plain (Non-Locking)
Collars

Clamp (Locking)
Collars

Fixed (Non-Rotatable)
Base

Adjustable (Rotatable)
Base