ULB-350 Underwater Beacon

Price on Application

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The ULB-350 underwater beacon is a compact, rugged and reliable acoustic signalling device used for marking equipment and underwater sites. Ideal for applications when size and weight are an issue.

The ULB-350 can be ordered in many configurations in terms of acoustic power output, frequency, and time delay. Using an off-the-shelf 9 volt battery adds the advantage of cost-effective maintenance. The ULB-350 continuously sends out an acoustic signal for up to 40 days.


  • Operating frequency: 9 or 45kHz +/- 1kHz
  • Acoustic output: 163dB at 1m
  • Pulse repetition rate: 1 pulse per second
  • Pulse length: 10ms
  • Activation: Water switch (other options available)
  • Power source: 9V alkaline or lithium battery
  • Operating life: 20 days with alkaline battery 40 days with lithium battery
  • Operating depth: 1216m
  • Weight: 217g
  • Housing dimensions:
  • Length: 7.9cm
  • Diameter: 4.3cm
  • OptionsFactory-set frequencies from 9 to 45kHz.
  • Time delays from 1 minute to 3 months.
  • Extended operational life.

Delivery, Returns & Instore Collection

When will I receive my order?

International Delivery Times

Monday – Friday 3 – 5 Working Days

UK Mainland Delivery Times

Monday – Friday before 2pm Next Working Day
Monday – Friday after 2pm 2 Working Days
Saturday & Sunday 2 Working Days

UK Extended Areas Delivery Times

Monday – Sunday 3 – 5 Working Days

Please note delivery times may be extended during busy periods.

EU Areas

Please note that due to changes by HMRC, orders being shipped to EU countries will not be shipped on the same day as they are invoiced. EU Orders will now be shipped on the next working day. This only applies to E.U. orders. Domestic and Worldwide shipments remain the same.

Collect In Store?

When you go to the online checkout, you can opt to collect your items in store. We'll let you know when your order is ready for you to collect. Your order will normally be ready to collect the next working day.

Returns, refunds or exchanges?

You can return any item within 28 days of receipt for a refund, provided the item is unused, in its original packaging and in 'as new' condition.

Items will be refunded in full (less postage) if received within 28 days from the date of despatch.


We aim to deal with all returns and exchanges on the day they arrive, however please allow longer during peak periods.

You can return the item(s) by dropping them off in store or by returning the item(s) by post. We do not insist on a specific courier service for the return, so please use the most economical or appropriate method for returning the item(s).

Northern Diver (Int) Ltd
Appley Lane North
Appley Bridge

If an item becomes faulty after a period of time then please contact customer services (01257 254 444 or info@ndiver.com) prior to returning the item. We will either repair or replace the item at our discretion.

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Trade Customers

Northern Diver offers trade accounts to commercial organisations and to those who work in or around water. Please click here to register your details and find out if you qualify. Once your trade account has been confirmed you can view all trade prices and shop easily online when logged into your account. Please note when you are not logged in to your trade account retail prices are shown. If you have any queries please do not hesitate to contact us. Tel: +44 (0) 1257 25 44 44.