Purchased a full box of these from a liquidation auction - cannot offer any technical support, hence the low price.  I have however tried one of these and downloaded the software on Android with no issues.

CURVEx NEO PRO EEG Headset - mental training through neurofeedback

The CURVEx EEG headset is a high-quality neurofeedback headband specially developed for mental training with EEG recordings (neurofeedback training). With 2 sensors on the front, the CURVEx offers excellent data quality for analysing the measured EEG signals and enables the raw data to be transmitted via various interfaces. The neurofeedback headband, equipped with the EEG chip, offers a simple design and high wearing comfort, so that the headband adapts perfectly to the head size and is suitable for children and adults alike.

Neurofeedback training can be used to train mental skills such as concentration, focussing, relaxation, mindfulness, stress reduction and general mental performance. This is done by the EEG sensors measuring the activity of the brain and providing real-time feedback via an app. These apps offer special neurofeedback games that specifically train different mental skills by monitoring brainwave patterns and integrating them into the training games in real time. The trainee thus continuously learns to perceive and control their personal mental state.
 

Features of the product:

• 2 sensors on the front
• Use of the EEG chipset
• Compatible with free apps for Android, IOS and Windows (CURVEx Website doesn't work, but Macrotellect Brainlink Software works - these appear to be the same or very similar devices.
• Bluetooth function for wireless data transmission
• Suitable for attention training, mindfulness training, neurofeedback training and more
   

Advantages of the product:

• Mental skills can be trained such as: concentration, focus, relaxation, mindfulness, stress reduction, mental performance
• Supports meditation
• In combination with comprehensive brain training apps and games, mental skills can be trained in a playful, entertaining way 
• Parent control over play times and access to EEG database
• High wearing comfort and simple design
   

Scope of delivery of the product:

• 1 x BrainLink Lite central unit
• 1 x Detachable electrode adapter
• 1 x artificial leather headband
• 1 x USB charging cable
• 1 x instruction manual/Quick Start Guide

Technical information of the product:

• Data acquisition of the EEG signals: TGAM chipset, RAW+eSense data
• Speed: 57600
• Connection: UART RS232
• 3x dry electrodes, 2x forehead electrodes (EEG, GND, REF), 1x ear clip electrode (REF, only with EC Advance)
• Compatibility: Bluetooth EBR, range of 10 m
• Platform: iOS/Android/Windows/Mac OS
• Battery: Lithium 3.7V 160 mAh, standby of 7-8 hours, runtime of 4-5 hours, charging time of 1.5 hours
• Vibration feedback with low power supply
• Certifications: Bluetooth SIG, FCC/SRRC, UL battery, made for Apple iPhone (MFi)
• Size: 40 cm circumference as elastic band, weight: approx. 40 g, colour: black
• Material: PU/metal alloy/PMMA
• Packaging size (LxWxH): 178 x 178 x 54 mm
• All apps are available in English

Important note: This product is not a substitute for medical treatment; a medical consultation is recommended for questions of well-being.   All of the above information is a translation from the Danish companies website - I don't know the exact specification for these products, so this is at the buyers responsibility.

I can share a link for where the compatible Apps can be located.