Nekos from Italy builds chain actuators for bottom-hung, top-hung and roof windows as well as rooflight domes. Common models are KATO, KATO 253 and KATO 305, each in 230 V or 24 V. If such an actuator is defective, you will find suitable Vent Systems chain actuators here.
In brief: As an alternative to Nekos chain actuators, Vent Systems offers the VS-KA with 250 or 400 N in 230 V or 24 V and stroke lengths from 100 to 1,000 mm. For two synchronised actuators on one sash there is the VS-KA-i. The bracket set is included in the price of the VS-KA.
Nekos chain actuators and alternatives compared
| Model | Manufacturer data | Alternative from Vent Systems |
|---|---|---|
| KATO 253 | 230 V or 24 V, 250 N push and pull, stroke 240 or 360 mm, IP30 | VS-KA with 250 N, stroke 250 or 350 mm |
| KATO | 230 V or 24 V, 300 N push and pull, stroke 100 to 400 mm, IP30 | VS-KA with 400 N, stroke 100, 200, 300 or 400 mm |
| KATO 305 | 230 V or 24 V, 300 N, stroke 200, 300 or 500 mm, the 24 V version also for smoke ventilation | VS-KA with 400 N, stroke 200, 300 or 500 mm |
| KATO Syncro³ | two synchronised chain actuators for wide sashes | VS-KA-i with synchronisation function, 24 V |
The VS-KA has IP32 protection, higher than the IP30 of the Nekos models mentioned. With 400 N instead of 300 N you also have a force reserve for seals and wind.
What to consider when replacing a drive
- Stroke: Choose the same stroke as the old actuator so that the sash does not open further than before. Calculate chain length
- Installation space and brackets: Compare the length and depth of the new actuator with the space on the frame. The old brackets usually do not fit, a bracket set is included in the price of the VS-KA.
- Voltage: 230 V actuators run directly on the switch, 24 V actuators need a control unit or power supply. 24 V or 230 V?
- RWA: If the 24 V KATO 305 is part of a tested smoke vent, agree the replacement with the window manufacturer or installer beforehand. smoke ventilation standards
- Connection: The actuator must be connected by a qualified electrician.
Photograph the type plate – we will name the right drive
Send us a photo of the type plate and the window via WhatsApp or e-mail. You will find the contact details on the contact page. You will receive a specific recommendation with a price, and stock items ship from Hamburg within 24 hours.
All manufacturers in one overview: Replacing window drives.
Frequently asked questions
Which actuator replaces the Nekos KATO 253?
As an alternative from Vent Systems, the VS-KA chain actuator with 250 N in 230 V or 24 V is suitable. Instead of 240 or 360 mm, choose a stroke of 250 or 350 mm.
Can I keep using the existing switch?
With 230 V actuators usually yes, the 230 V VS-KA runs directly on the switch. For 24 V actuators you still need a control unit or power supply.
What should I use for a pair of KATO Syncro³?
For two synchronised actuators on a wide sash, the VS-KA-i with synchronisation function in 24 V is suitable. Replace both actuators together.
Note: The brand and product names mentioned belong to their respective owners. They are used here only to indicate technical compatibility. Vent Systems is not affiliated with these manufacturers and offers only its own Vent Systems actuators. The manufacturer data is taken from publicly available data sheets (as of October 2026) and is for technical comparison only. Please check dimensions and values on the existing actuator before replacing it.