Chair bed on this website first of all means a wooden single size frame.
Made in 3 sections these frames are available as a futon with separate frame and mattress or in an upholstered style.
So, either convert in the same way. When flat its in a bed position and when converted it will be a chair.
Single size has a UK standard that's 3'0"/90 cm x 6'3"/190 cm. Furthermore another UK standard size is 2'6"/76 cm x 6'3"/190 cm.
On this site our upholstered version is a European standard size 90 cm x 200 cm. Various types of fabrics and many colour options accompany this option from global brand Innovation Living.