It is not a complete novelty, but the Mares Viper Pro DS 90 is the top of the line sling gun by Mares.

In brief

A double 16 mm diamater circular bands sling gun, the Mares Viper Pro 90 DS offers an inverted 100% stainless steel release mechanism, with open shaft rail and inferior line guide on the barrel, open muzzle, standard Vertical Spiro 65 Reel, and the new KJ grip for maximum control on the speargun.

Mares Viper Pro DS Grip Reel Draw Rid

The barrel

In black anodyzed alluminium with circular section and 28 mm diameter, the barrel is strongly reinforced along the vertical section thanks to two profiles that act, also, as stiffeners of the barrel. On its inferior part we find the line guide, which is made of a rail with 2 mm side walls, while on the upper part of the barrel the shaft guide has one 4 mm high rail. This permits a good improvement of the rigidity of the barrel on the vertical section, which is the most stressed by the load of the rubber bands.


Shaft guide permits to position shafts from 6 to 8 mm of diameter, and reduces friction of shaft on barrel, with minimal contact surface between the two elements thanks to the two rails.

On both ends the barrel is secured to the grip and the muzzle with a stainless steel pin of 5 mm diameter, while the water resistant sealing effect is obtained by two O-Rings, both on the grip and on the muzzle side.

The muzzle

The muzzle is extremely compact and, even though designed with an open solution, it is complete with a base for an arch to close the muzzle on the upper part, simply mounting it with a stainless steel pin. Both elements are included standard. The design of the muzzle is a single piece completely made of glass loaded Nylon. The shaft rail on the muzzle connects perfectly with the one on the barrel. The design of the muzzle is made for mounting two circular bands, where the passages are open to permit changing them quickly simply passing them on the Dyneema side along the openings of the muzzle. The structure, moreover, avoids the overturning of the bands at the end of the shooting phase.


The only metal part of the muzzle is the steel wire in the lower part for the passage of the line. The material of the wire helps to avoid wear generated by the wire quickly sliding along when a prey, especially if big, is caught.


Handle and grip

Key component of any speargun, the grip of the Mares Viper Pro DS 90 is extremely interesting. Very valid is in fact the solution of the preformed and dismountable grip, made with soft rubber in Mares orange colour. The desing is innovative, with a large base to stabilize the grip of the hand and optimize brandishing. This is done thanks to the fact that the lower part of the palm can make a better lever on the grip. Both the rear orange part of the grip and the frontal part in glass loaded Nylon offer carved surfaces that optimize, together with two lateral areas with rough surface, anti-slip effect.


Grip is symmetrical and so adapt to both right and left handed. A difference in the two cases is the fact that on the right side the security lever is present and can be easily felt with the base of the index finger, when it is lowered to lock the release system. When security is off, the lever is in the horizontal position, and so not felt anymore. This also works quite well for left handed, as they will feel the lowered lever with the thumb. On both sides concave profile will permit additional comfort and adaptation of the hand. Also, the a small wing is present on both sides of the handle to lower the line, which is an interesting solution to keep the line tidy and away from line of aim.

Release mechanism

Release mechanism is an additional key element of the Mares Viper Pro DS. The system utilizes a stainless steel mechanism, manufactured through the advanced technology of the micro-injection, that permits an extreme precision in the dimensions and measures of parts and, consequently, a greater smoothness of the shot. Together with this is the fact that the system is inverted, another solution that helps sensibility and feel on the trigger.



The shaft is the tahitian Hardy, made of 17-4 PH steel of 6.5 mm of diameter, with traditional round tip and upper barb completely external to shaft. The connection points with Dyneema® wishbone are insured by three shark fins, all with one hole to pass the line through and connect the shaft to the line in an advanced position. Also, shark fins are manufactured with mycro-injection technology, so that final result is smooth edges that do not cut the line.

Elastic bands

Mares Viper Pro DS 90 is set standard with two circular 16 mm diameter S-Power Speed elastic bands. The bands have a progressive behaviour and are made of Latex, maintaing their performance in time. Elongation factor is 3.


Available are the two reels Vertical Spiro 65 and Vertical Spiro 87. The numbers indicate the diameter of the coil of the line. On the sling gun received the reel is the 65 version. The attachment system of the reel to the speargun is on the front part of the hilt of the trigger and utilizes a specific Mares system, with resistant and rigid arm made of glass loaded Nylon. This connection is very strong, rigid and easy to dismount just releasing a screw and a steel pin.


The clutch of the Vertical Spiro is Mares patented and appears to be pretty simple and intuitive in use, where instead of having the classic wheel for adjusting toughness, usually of small dimensions, it has a wide flat element with two extensions where to hold the system and easily adjust the clutch using the entire hand, instead of only the fingers. This is an important aspect considering that such operation is usually done with more or less thick neoprene gloves.

A dismountable steel wire is used to pass the line and keep it in the right position and close to the center of the reel. Such wire tends to flex putting the line in tension, an aspect that works as pretensioner of the line.

Sternal support

Another interesting element, specifically designed by Mares, is the sternal support of the Viper PRO DS. Such component, made of glass loaded Nylon, has a solution that uses a variable deformation system, thanks to the hallow area between the main body of the component, which appears extremely strong, and the load surface, which is thinner and deforms. This contributes to the adaptation of the shape of the sternal support to the chest of the spearo, making the loading of the speargun more comfortable.


To download and print the complete technical data sheet of the Mares Viper Pro DS 90 click here.

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