Core is Specna Arms' line of airsoft actuators, marketed as a solution for both beginners and experienced players. According to the manufacturer, the line combines an attractive price, high quality materials and a convenient quick-change spring system.

It is this reason that carries the authentic, licensed markings of the real weapon manufacturer - Rock River Arms. This company is engaged in the production of spare parts and accessories for weapons, but also, most importantly, high-quality AR-15 carbines. Rock River Arms was founded in 1996 by the Larson brothers with Les Beer; the main office is located in Colonna, Illinois. The RRA is currently executing contracts for the supply of AR-15 carbines to the FBI, DEA and the US Marshall Service.

The receiver of the drive, the buffer tube of the compound stock (which is also the location of the battery) and the pistol grip are made of high strength plastic, reinforced with nylon fiber. Most of the other parts, including the outer barrel, forend with RIS, muffler and enlarged bolt handle, are made of metal (all bolts and pins, as well as dummies of the bolt and the ejection port of the sleeves are steel). The receiver bears the RRA mark and a serial number.

The upper and lower parts of the receiver are very carefully matched to each other, so there are no gaps or backlash between them. The use of lightweight materials made it possible to reduce the overall weight of the drive, which is useful during dynamic collisions at short distances and long gaming "marathons". In addition, the manufacturer claims that due to the reinforcement with glass fiber, the case lasts longer than similar products made of plastic or even metal.

Another interesting feature of the product is the ESA mainspring quick change system, which makes it easy to adjust the power of the shot to the requirements of a particular range. To replace the spring in such a system, it is enough to remove the buffer tube. This can be done in the field, outside of special workshops and without additional tools, moreover, there is no need to remove or disassemble the gearbox. The benefits of this design cannot be overemphasized given that different teams and organizations may have different drive power requirements. ESA allows you to install a variable spring with minimal effort and time, thus choosing the best initial ball speed and providing an optimal balance between efficiency on the one hand and safety for the players on the other. It should be noted that the actuator is supplied with a variable spring M90, ideal for close range combat, particularly in buildings. It reduces the initial velocity of the ball to 90 m/s, while the standard combat spring gives about 116 m/s and is designed for medium combat distances.

The drive is fully compatible with Li-Po and Li-Fe batteries. Ni-Mh battery included as standard.

The gearbox uses 8mm bushings. The piston is made of lightweight polycarbonate plastic and is complemented by a steel toothed rack for added strength and reliability. In addition, the features of the "interior" include a type 1 cylinder, four anti-reverse pawls and a steel single-fire cutter; safety factor of all parts allows their use with M140 springs.

The high-quality rotary-governed hop-up camera in this model is paired with a precision 6.03mm inner barrel, which the manufacturer claims provides high range and accuracy. However, it should be remembered that all these possibilities can be realized only with balls of the appropriate quality.

The drive is equipped with a RIS top guide, a RIS jet set and an adjustable telescopic stock. The rear sight has a complex design, due to which it does not interfere with the use of additional sights - in particular, collimator or optical. The buffer tube of the butt has a surface that prevents slipping - it is due to this surface that the butt is fixed, it makes it possible to adjust its length with an accuracy of literally up to a millimeter. The flame arrester is installed on a left-hand thread with a diameter of 14 mm, it can be replaced with a dummy silencer

The set includes an S-MAG hopper magazine for 380 balls, made of durable plastic. S-MAG is an exclusive development of Specna Arms, it has a characteristic surface texture with the manufacturer's logo and, according to the creators, ensures uninterrupted supply of balls even at high rates of fire.

Equipment:
- drive unit;
- Score;
- Mechanical sighting devices;
- RIS overlays;
- handle for transferring fire;
- Variable mainspring;
- Battery;
- Charger.

Characteristics:
Ball initial speed: ~ 90 m/s
Gearbox version: v2
Gearbox bearing diameter: 8mm
Hop-up +, customizable
Length: 695/780 mm
Inner barrel length: 290 mm
Barrel thread: 14mm CCW
Quick spring change: +
Materials: metal, steel, plastic (reinforced with nylon fiber)
Weight 2400 g
Battery included: + (Ni-Mh, 9.6 V, 1100 mAh)
Store type: bunker
Store capacity: 380 balls