If you discover that your RAD8, RAD7, or Durridge accessory is malfunctioning, we recommend that you first call Durridge and talk to a technician. A surprising number of minor “disasters” can be avoided by long-distance consultation. The next step, if consultation fails, is usually to send your instrument in for evaluation and repair. Please complete the Instrument Return Form as described below, and be sure to include a short description of the problem, along with any documentation of the problem that you might have (notes, printouts, etc.) Within 48 hours of our receipt of the instrument, we will call you to give a diagnosis.

Bear in mind that RAD8 and RAD7 repairs involve a re-calibration of the instrument, which takes time. If you need a RAD8 or RAD7 during the repair time we may be able to provide a loaner instrument.

Shipping Information

1. Before you send a RAD8, RAD7, or Durridge accessory back to us, please complete the Instrument Return Form and email it to Durridge at . Include a printed copy of the form in the box with the device. You can send your shipment to either of our facilities (USA or UK), listed below (see important, specific instructions for each below).

2. We typically need a RAD8 or RAD7 in house for 10 business days, provided it has no serious problems. Once it has been serviced, your instrument will be shipped back to you after payment is received, so the total time the instrument will be away from your facility is typically 10 business days, plus the time it takes the receive the payment, plus the time the instrument spends in transit. If additional service or repair is required, this may delay the return of the instrument. Durridge accessories such as DRYSTIKs may take less time to service, depending on the issue.

3. When sending a RAD8 or RAD7, please send the instrument only, without the cables and accessories. Pack the instrument upright in a box with one-inch (2.2cm) padding all around. A 14x14x14in (or 36x36x36cm) box is suitable. Pack the box well, and seal it carefully. The RAD8 may be sent in the inner box in which it was originally packaged.

4. International customers must be very careful, to avoid substantial extra shipping charges and delays, both for shipping to the nearest calibration facility, and for its subsequent return.

5. Commercial Invoice check-list (for international shipping only):

  • For your courier or freight forwarder, you will need to provide a Commercial Invoice.
  • Please write only in English on the commercial invoice.
  • Use the following description for a RAD7: “Used RAD7 Electronic Radon Detector”. For a RAD8, use “Used RAD8 Electronic Radon Detector”. For Durridge accessories, use a similar description, including the name of the accessory.
  • Insured value US$1,500.
  • Please state on the invoice that the instrument is MADE IN USA and that it is being “returned to the manufacturer temporarily for repair and recalibration“.
  • Please use the HS (Commodity) code 9030.10.0000.
  • Please mark the box with the serial number of the instrument (as the RMA – Return Merchandise Authorization).
  • Please add the phone number of the Calibration facility you choose, in case the Customs Office wants to call us.
  • Next, you must ensure that your courier (i.e. UPS, FedEX) or freight forwarder will deliver the package to our door. The formal “INCOTERM” for this is “DDP”, which means “Delivered Duty Paid.”
  • We will not pay or be responsible for USA or UK import duties, or Customs clearance charges. Your shipper must be told this when you arrange your shipment.
  • It is important to make sure you prepare all the documentation you need to reimport the goods back into your country without being charged.
  • For the Return to you: unless you instruct us otherwise, we will return your Durridge instrument via the same shipping method you used to deliver it to us, Freight Collect. Durridge can pay for the return shipment CPT (“Carriage Paid To”) to you, but our cost will be invoiced to you before shipment.

If we can help further, please email us at

Specific info for SHIPPING TO OUR USA FACILITY (from outside the USA)

Durridge Company, Inc.
900 Technology Park Drive
Billerica, MA 01821-2812, USA
Phone: +1 (978) 667-9556
Fax: +1 (978) 667-9557

Declaration Form

  • There needs to be documentation proving that the instrument was previously imported into your country, otherwise you may be charged import duties when the instrument is returned to your country.
  • Please fill out the declaration form provided below. Attach the completed declaration form to the commercial invoice. If the invoice is scanned and submitted electronically, please scan the declaration form and submit it electronically as well.

Foreign Shippers Declaration of US Goods Returned (PDF)


Durridge UK Ltd.
Sheffield Technology Park
Cooper Buildings
Arundel Street
Sheffield S1 2NS, UK
Phone: +44 (0)114 221 2003

Please complete the checklist in the above section. It is very important to include the HS (Commodity) code 9030.10.0000, otherwise import duty may be charged at the UK border, for which you will be liable. Please also include our EORI number GB219670885000.

Please ensure that you make the necessary arrangements with the Customs authority in your territory for the return of your instruments. There may be special procedures for temporary exports. For example, you may need to provide documentary evidence that the instrument was previously imported into your country, to avoid being charged import duty again.

Instrument Return Form

Fill out this form before returning a RAD8, RAD7, or Durridge accessory to Durridge for repair:
Instrument Return Form (PDF)

Warranty Information

Durridge Limited Warranty (HTML)