I try to find this information for almost 1 year
Never get an answer fron Nexto, except the information sheet "How To Replace The Battery In Your Device" published march 2011
Representative in France does not have parts or information
Answer by Chris2012-02-29
The UK distributor have the replacement battery for ND2700. Contact firstname.lastname@example.org for pricing and delivery charge for your country. European customers only though.. Hope this info helps.
Answer by Chris2013-05-29
Please note the UK distributor no longer ship outside the U.K.
You can purchase the replacement battery directly from NextoDi at http://www.nextodi.com/acc_store/acc_store.php