Fairy lights, seven run on button batteries and one says how long

Twenty three strings of copper wire fairy lights from one search, none of them handled here. The thin wire with a bulb every few centimetres that goes in a jar, round a mirror or up a tree. The solar ones are in the garden lights guide.

What powers it is the whole decision. Seven run on button batteries, and only one says how long the batteries last.

Which you are buying

Most are the same plain wire in copper or silver, now and then green or red, and the shapes are extras. Three are wine bottle corks, three put ghosts and pumpkins, cat paws or pearls and leaves on the wire, one is a pod that sits under water in a vase, and one is a string of colour changing bulbs run from a phone app.

USB, AA or button cells

USB is the easy answer anywhere near a socket. A phone charger, a laptop or a power bank runs it, there is nothing to change, and the plug is one you already own.

AA cells are for a table, a shelf or a mantelpiece with no socket nearby. A box of two or three holds several times the charge of a pair of coin cells, and spare AA are in every corner shop.

Button cells make the smallest holder, small enough to hide in a cork or under a jar, and they run flat first. The one listing that gives a battery life puts its three LR44 cells at more than 72 hours and says a pair of CR2032 goes dim after 24. That is a seller comparing itself with everyone else, and it is still the only hour figure on the page.

Button batteries

Seven listings run on CR2032 or LR44 coin cells: four in a small holder on the end of the wire, three inside a cork. Trading Standards guidance on button batteries asks for a battery compartment that needs a tool such as a screwdriver or a coin to open, or two separate movements made at the same time, because a swallowed button battery can burn through the tissue around it.

Six of the seven show the holder open or the cells out, and not one of the six shows a screw or a tool: a lid that flips up, a tray that slides out of the cork, a pod that twists apart, a stack of cells that pushes into the end of a cork. The seventh, also a cork, is drawn with its cells behind a cover held by a small cross head screw, the only one on the page, and it is a drawing rather than a photograph. None of them is for a room a toddler can reach. In a house with small children, buy USB or AA.

Length and bulbs

Where a listing gives a length and a bulb count together, it is ten bulbs to the metre: 2 metres with 20, 5 with 50, 20 with 200. A longer string is more of the same, not brighter.

The titles list every length on offer, from 1 metre up to 30, and one red wire string titled 20 metres and 200 bulbs shows 5 metres and 50 bulbs on its own battery panel. Check which length the price is for before comparing two.

What was left out, and why

The 50 and 100 metre green string runs from a mains adapter with a two round pin European plug, which needs an adapter in a UK socket. The app controlled string is a different thing, a strand of colour changing bulbs that needs a phone to work it. The firefly string that gives 72 hours, the underwater pods and a ten pack sold as wholesale all run on button cells, and the firefly string and the underwater pods cost more than anything else here. One USB string with a remote is left out for a designer’s name on a gift box in one of its photographs, and its own diagram says it has no timer. The cork listing drawn with a screw over its cells gives no size and no battery type, and one of its photographs is a bar shelf of branded spirits; the third cork listing’s panel is in garbled English. The rest are the same plain string as the picks with less in their photographs.