OCTOBER 2009 UPDATE - THESE ARE IN VERY L@IMITED SUPPLY NOW !! These are BRAND NEW old new stock Sinclair ZX81 kits - but for sale here in 2004 !! They were built here in the UK , then shipped to the USA and stored for nearly 20 years , then we bought them and shipped them back to the UK again !! Each kit contains all the necessary parts, including keyboard, case, printed circuit board, resistors, capacitors, connectors, integrated circuits, power supply, cables etc. When completed the computer can be used on UHF Channel 33 of any Black & White or Color TV. It is possible to use the computer on UK (50 hertz) and US (60 hertz) televisions by setting a 'jumper' on the circuit board. All parts are high quality and the glass epoxy PC board has a clearly silk screened parts legend. Each kit contains all the necessary parts, including UK keyboard, case, printed circuit board, resistors, capacitors, connectors, integrated circuits, power supply (110v), cables etc. Assembly instructions are included in with your ZX81 kit , and are also available in the Kits Assembly Instructions section online here as well should you need them. Also comes with a FREE ZX81 book as these kits where originally for the USA so had no UK manual, so we give you a free book in its place !! When completed, the ZX81 computer can hook up to Channel 33 on any black & white or color TV for its video display (UK (PAL) and US (NTSC) Compatible - selectable by jumper when the kit is being assembled). It has a complete (English) BASIC language interpreter in ROM memory, and it can save and load programs on standard cassette tape recorders (these are available from Retro-Trader.com if you need one). The kit's five Integrated Circuits make clear the architecture of a typical computer. Processor (1) , ROM (1), RAM (2) , and Glue Logic (1). As the kits were originally intended for the South American market, they come with a 120V power supply , but generic 9v 0.7A power supplies are available are available , sometimes we have them in stock also. What do you get for your money ? First you get a computer that if you choose to build it will give you , your children , and your friends many happy hours of interest and fun , how many computer kits exist on the market today , not many if any , would you not prefer your child to build and know what a computer is really about , rather than just play games on a modern one ? You get a computer that is a piece of history , a computer that while over 20 years old , has been preserved and stored and is boxed like new. You get one of the original build your own kits , which are much rarer than a built ZX81 , as most people opted to buy a complete built one. What you are getting in our opinion is an investment also. Whilst of course nothing is guaranteed , the numbers of these kits are limited , and are on a first come basis , all I can tell you is that in the last few years , as retro computers and games have increased in popularity , demand has shot up , and so have prices , and a good example of the way it might go , might be the ZX80 computer , to find a reasonable condition working one in just its poly box you are generally looking at £400+ , to find an unbuilt boxed KIT ZX80 you must be looking at over £1000+. Of course we cannot promise this will happen with the ZX81 Kits , but as these are brand new , as good as they get condition kits , and in limited supply , in a few years time do you want to be kicking yourself ??? You must be aware that if you choose to build the kit we do not provide a building service for you , and that whilst we provide full instructions for building with the kit and also extensive online instructions and resources on this site we cannot be held responsible for any damage you do to the kit , yourself or property, or other people, if you choose to build the kit , also if you damage a part or whole of the kit in building it , we cannot be held responsible for this. The kits come as per the descriptions and photos on this site , and as a whole are in better condition than most , or many things you would buy boxed from a shop today , but small blemishes do occur due to the age of the items , but in general the items are 98-100% as new , but to allow for the odd blemish we state this condition here. As far as we are aware there is a minimal component failure percentage on these kits , certainty no more than would have been normal had you bought them from the shop 20+ years ago , and should you find an electronic component fails they are easily obtained from current electronic component suppliers. We do not , and cannot repair , replace or supply any of these parts , and whilst we do not anticipate problems with peoples kits , once bought they are your responsibility. We will not exchange , replace , refund of return any ZX81 Kit , or hardware , sold via this site because of this , but all items are in as described condition when they leave us and are sold on , 'an as seen' basis , but if we say they are working they are working !