"Cheating watches" have started to surface in classrooms in Britain, sparking concerns among teachers that such gadgets can give students an unfair advantage in exams.
According to the BBC, the unassuming watches, which are easily available online, are able to conceal up to 8GB worth of data or information which can be read during exams.
There is also an "emergency button" that allows the user to quickly switch from hidden text to a conventional digital clock face.
Stressed students can be tempted to cheat, said Mr Joe Sidders, deputy head at Monkton Combe Senior School in Bath, who warned about the scale of this "hidden market".
He also raised concerns that if such devices were in wide circulation it would call into question the validity of results, BBC reported.
A quick search on the Internet showed at least five "cheating watches" being sold on Amazon, and two on eBay, all costing less than S$100.
One of the watches is described as "specifically designed for cheating on exams with a special programmed software", according to a seller.
Users can upload various types of files onto the gadget, including photos, music and videos, and it even supports up to 27 languages.
The watch has received mixed reviews, with some claiming most people think that it looks like an iWatch, and others saying that it is possible to even use it on the front row during an exam.
According to the Mirror, Britain's Joint Council for Qualifications said: "A candidate found in possession of anything used for cheating - like these watches - would be reported to the awarding organisation whose examination was affected.
"This could result in the student being disqualified from the exam and the overall qualification."
In response to queries from The Straits Times, a Ministry of Education spokesman said students are not allowed to have with them "electronic devices capable of storing and/or transmitting information, during their examinations".
A spokesman from the Singapore Examinations And Assessment Board (SEAB) added: "SEAB takes a serious view if any candidate is found to have breached any of the examination rules and regulations, and they may be prohibited from taking the examination or have their results terminated."