How long will it last on a full charge?

It can be used for 5~8 hours and the charging time is 3~5 hours.

What payment methods can I choose for wholesale orders?

We support credit card payment and PayPal payment. For wholesale orders, we also support T/T transfer. It should be noted that we do not accept cheque payment.

How about if there is any defect in my order?

If it is confirmed that there is a problem with our product, we will arrange a new product for you.

When I can receive my order

It usually takes 3-5 days to receive the product.

Where is the wb001 ship from?

We have inventory of WB001 in Amazon warehouse in the United States and can arrange delivery.

How exactly does it charge, can i use a plug with the USB port like my phone has or do you need to plug it into a computer?

Both ways you mentioned are OK!
You could use a plug with USB port like your phone you has to charger the voice amplifier unit.
You could also plug the unit into a computer.

When I first plugged in, I saw a blinking red light, then the red light stopped blinking, but stayed red. Does that mean it is at full charged now?

Yes, if the red light stayed red it meas it is fully charged.
The red light flahes while charging.

Will I have to pay any sales tax?

Tax is charged by Customs offices in the destination country based on their rules and policies.
 customer is responsible to find out the situation in their country. Shipments from all of our warehouses are delivery duty unpaid. 
Therefore, If any, these charges must be paid by the customers. Customers take full liability for all return shipment costs, customs
 charges and handling fees should they refuse to accept a parcel due to import duties or taxes. Please note that according to customs
 regulations, WinBridge cannot declare purchased items as a gift or list an amount that is lower than the actual product price.

Does the Bluetooth connection work with an iPhone?

Thank you for your question.
For WB001 there is no Bluetooth include.
We would recomand you the S208 which is with Bluetooth 5.0 and perfect for woking with iPhone,iPad or Mac.

https://www.winbridgestore.com/products/portable-voice-amplifier-with-microphone-headset-wired-1800mah-rechargeable-bluetooth-speaker-with-headset-microphone-personal-amplifier-for-teachers-tour-guides-coaches-elders-etc

Now we have dark Blue color available. Please let me know.

Can you play music files from a USB flash drive? If so, how is this done?

yes, Wb001 can play files ( MP3 formate) via USB flash drive, you can plug your USB to the amplifier and it will play the files in it for you.

How many watts?

The WB001 is a 5 watt amplifier.

The USB cable and user manual for my unit have been misplaced. Can you send the digital manual please? And what kind of cable should I use? Thank you.

Please kindly send us your email address, we will email you the PDF user manual, and the cable is mini interface.

Can two headsets be used on the same amplifier? We use this device to speak to my mother who is very hard of hearing. She holds the speaker up to her ear. It would be nice to be able to have two people talk to her at once.

So sorry, one WB001 speaker can only be used with one headset at once. Our model S92 pro or S92 plus can be used with two microphone at once.

IS IT POSSIBLE TO ATTACH A LAPEL MIC TO THIS UNIT?

A alapel mic can be attached with WB001, however you can only attached one of them( alapel mic or headset mic).

Is headpiece adjustable?

No, the headpiece is not adjustable, only the mic. The headpiece is made to fit the crown of the head so there is no need for adjustment. The mic lays along the cheek/jaw and the mic can be bent to place in front of the mouth. Works very well.