A mid-size F9-5 for trails and commutes: IPX7 touch buds on Bluetooth 5.1, and a 1,500mAh case with an LED readout, a USB output and a rubber cover over its ports.
The Voltstech F9-5 sits between the slim F9s and the big power-bank bricks. Its case holds 1,500mAh, shows the charge of the buds and the case on an LED readout, and has a USB port on the side for other devices.
Mid-size is the whole point. The case fits a jacket or a hip pack on a trail, yet still carries a reserve for your phone. Voltstech also makes the buds ergonomic and light, built to sit in the ear through runs, rides and hikes.
Be honest about the phone top-up. A 1,500mAh cell loses a share of its charge to conversion. Expect roughly a fifth to a quarter of a typical modern phone battery, and Voltstech itself warns that charging a phone drains the case quickly.
The buds carry 50mAh cells and 8mm speakers with a composite diaphragm. Voltstech aims for deep bass and clean treble with less distortion. Four spare silicone tips ship with it, so most ears find a fit.
The brand on the box is YUSHENG, with Voltstech in the product name. Same pair, two labels, a common story with F9s.
| Spec | Value |
|---|---|
| Model | F9-5 (brand YUSHENG, sold as Voltstech) |
| Bluetooth | 5.1 + EDR |
| Profiles | A2DP, AVRCP, HFP, HSP, SPP |
| Rated range | 10 m (33 ft) |
| Drivers | 8mm, composite diaphragm |
| Bud battery | 50mAh each |
| Play per charge | 4–5 hours |
| Talk per charge | 4–6 hours (maker quotes both) |
| Case battery | 1,500mAh (headline figure) |
| Case output | USB port to charge other devices |
| Battery display | LED for buds and case |
| Port protection | Silicone dust cover on case ports |
| Water rating | IPX7 |
| Call processing | CVC 8.0 noise reduction |
| Controls | Touch: skip, volume, calls, Siri |
| Pairing | Buds pair to each other when lifted out |
| Bud charge time | About 1 hour |
| Case charge time | About 2 hours |
| In the box | 2 buds, charging case, cable, 4 spare silicone tips, manual |
| Colour | Black |
Dust gets everywhere on a gravel ride or a dry trail. Voltstech covers the case's charge and USB ports with a silicone flap, so grit stays out of the contacts.
That small flap solves a real problem. Dust in a USB port leads to loose connections and a case that charges only when the plug is held just so. Closing the cover after every charge keeps the ports clean for longer.
| Threat | What covers it |
|---|---|
| Sweat on the buds | IPX7 rating |
| Rain on the trail | IPX7 rating |
| Dust in the case ports | Silicone cover |
| Wet case | Keep it in a pocket; the rating covers the buds |
The IPX7 test is a 30-minute dunk at one metre. A downpour on the descent, a dripping forehead on the climb: both are well inside it. Rivers, pools and hot springs are not.
Voltstech pitches the buds for running, working out, biking and hiking, with a snug, stable fit. They use tips only, no hooks. For hard trail running, test the fit on a short loop before a long one.
Charging figures are straightforward: about an hour for the buds, about two for the case. The F9 charging walkthrough covers reading the LED digits and when to charge.
Winter trails need one extra habit. Cold drains the small bud cells faster, so tuck the case under a jacket layer until the start.
Phone zipped away, both hands on the bars. The Voltstech buds handle the basics by touch, so the ride never stops for a menu.
Check the F9 touch-control manual for how many taps each one takes. Practise them once at home; gloves and bumps make it harder on the road.
Calls get CVC 8.0 noise suppression, which strips steady background hum from your voice. Voltstech also supports the HFP and HSP profiles for calls and A2DP plus AVRCP to stream music and skip tracks. Traffic and wind will still reach the mic, so pull over for a long call.
Phone-specific steps live on pairing F9 earbuds. If a bud stops talking to its partner, the F9 reset steps fix it.
Bluetooth 5.1 with EDR is a step behind the newest 5.3 buds but steady for music, podcasts and calls. Voltstech rates the range at 10 metres and says games and calls should not lag. Casual play feels fine; competitive shooters may notice a delay, as with most Bluetooth buds.
Riding in traffic? Keep the volume low enough to hear what is coming up behind you. The IPX7 rating takes care of the rain; your ears take care of the cars.
Works with iPhone, Galaxy, iPad and any other Bluetooth audio device. No app needed.
Case size is the real choice among F9-5s. The Voltstech sits in the middle, and that suits a lot of people.
| Pair | Case | Ports | Bluetooth |
|---|---|---|---|
| Voltstech F9-5 | 1,500mAh, LED | USB out, dust cover | 5.1 |
| MDNS BTH-F9-5 | 2,000mAh, LED | Not stated | 5.0 |
| Avalanche Market F9-5 | 2,000mAh | Phone power | 5.0 |
| BMHOLU F9-5 | 500mAh | Buds only | 5.3 |
Pick the Voltstech if the dust cover and a newer chip than the 5.0 pairs appeal, and a smaller top-up is enough. Pick a 2,000mAh F9-5 if the phone needs a bigger rescue. Pick the BMHOLU for ear hooks and the lightest case.
Weekend riders will find 1,500mAh plenty for the buds. Travellers who lean on the case for the phone every day may want the bigger cell.
Carry is where the middle size pays off. A 1,500mAh case fits a hip pack or a jersey pocket better than a 2,000mAh brick, yet keeps the LED readout and the USB port that slim cases give up. Buds and case come in black only.
To weigh it against every other F9 version, open the F9 version comparison. For what each case size costs, see the F9 price breakdown.
Yes, through the USB port on the case. From 1,500mAh, expect roughly a fifth to a quarter of a typical phone battery, and a quickly drained case.
Voltstech's headline figure is 1,500mAh, while one spec line says 2,000mAh. Plan on 1,500mAh.
Yes, the buds carry IPX7. The case has a silicone cover over its ports but should still stay dry.
About 4–5 hours of music from the 50mAh cells, with talk time quoted at 4–6 hours. The buds recharge in about an hour.