Free rapid Covid home testing kits are being offered to anyone who cannot work from home and all secondary school pupils in Wales.
They are for people who have no Covid symptoms and give a result within 30 minutes.
The Welsh government hope that improving the availability of lateral flow tests will make regular asymptomatic testing for coronavirus more convenient and accessible for people.
As many as 1 in 3 people may have Covid-19 without displaying symptoms which means asymptomatic testing is an important means to keep people safe as restrictions are gradually eased.
Who can get a test?
Rapid home testing will now include all those who cannot work at home and all secondary school pupils, from Year 7 and above.
Schemes are already in place for some workplaces, childcare settings, schools, colleges and universities.
It is advised to do a test twice a week.
How do you take a test?
Taking a lateral flow test involves using a swab to take a sample from the back of the throat near the tonsils and from the nose.
The swab is dipped into an extraction solution. This is then dripped onto the device's paper pad, producing a reaction that gives the result.
The result will be visible on the device 30 minutes after the sample is applied. Unlike a PCR test, there is no need to send the sample to a lab.
Dr Amir demonstrated how to do a test on ITV's Good Morning Britain.
How can I get them?
From Friday 16 April, you can pick up self-test kits at certain testing sites.
Each person can collect 2 packs of 7 self-test kits for home use. You do not need an appointment.
Test centres are open for collection 7 days a week.
At most testing sites people will be able to collect the rapid lateral flow tests between 08:00 and 13:00.
Sites will close for a deep clean and re-open for symptomatic PCR testing between 14:00 and 20:00 each day.
Where can I collect them?
Aberdare, Coleg y Cymoedd Campus Car Park (8am to 1pm)
Aberystwyth, Canolfan Rheidol (Ceredigion County Council HQ) (9.30am to 12:30pm) Drive-through only
Bangor, Dean Street Car Park (8am to 1pm)
Barry, Colcot Sports Centre (8am to 1pm)
Brecon, Watton Car Park (8am to 1pm)
Bridgend, Bowls Centre Car Park (8am to 1pm)
Caerphilly, Rhymney, former Aldi site, Old Brewery Lane (8am to 1pm)
Cardiff, Ely (8am to 1pm)
Cardiff, Museum Avenue (8am to 1pm)
Cardiff Bay, County Hall Car Park (8am to 1pm)
Carmarthen, Carmarthen showground site (9.30 am to 12.30pm) Drive-through only
Haverfordwest, Pembrokeshire Archives (9.30am to 12.30pm) Drive-through only
Llantrisant, Royal Mint Visitor Car Park (8am to 1pm)
Llanelli, Dafen Yard (9.30am to 12.30pm) Drive-through only
Merthyr Tydfil, Leisure Centre (8am to 1pm)
Neath, Milland Road Car Park (8am to 1pm)
Newport, Bettws Social Club (8am to 1pm)
Newport, Duffryn, Duffryn Arms Pub Car Park (8am to 1pm)
Newport, The Old Kwik Save Car Park (8am to 1pm)
Newtown, Shortbridge Street Car Park (8am to 1pm)
Pontypool, Old Mill Car Park (8am to 1pm)
Rhyl, Quay Street Carpark (8am to 1pm)
Shotton, Civic Hall, Connah's Quay (8am to 1pm)
Swansea, Grand Theatre (8am to 1pm)
Wrexham, Memorial Hall (8am to 1pm)
How accurate are lateral flow tests?
Concerns have been raised about the accuracy of lateral flow tests by some scientists.
The World Health Organization (WHO) has pointed out the accuracy of the tests can be affected according to the time from the onset of infection - meaning they are more likely to detect positive cases when viral loads are the highest and patients are most infectious.
This is typically one to three days before the onset of symptoms and during the first five to seven days after the onset of symptoms.
It could mean that lateral flow tests are less effective at detecting the virus in asymptomatic people.
But the Welsh government maintains lateral flow tests are "specific and sensitive enough to be deployed for mass testing, including for aymptomatic people" after extensive clinical evaluation from Public Health England and the University of Oxford.