I gave this to my daughter last Xmas, when she was 19 mths old, 10 months later, it is still very popular in our house.
In the set you have all the letters, in uppercase form, from the alphabet; and a "reader". All parts are magnetic, so as my daughter found will stick to our fridge, freezer, washing machine and tumble drier! She's had great fun moving this around our kitchen.
When a child selects a letter and puts it in the reader, the reader cleverly knows which letter it is, says the sound the letter makes then sings a song. Also the reader will sing the alphabet when a button is pressed. It has an on-off switch and two volume levels.
My daughter quickly realised how to put each leter into the reader, and in the early days was quite happy doing that and doing a little dance when the song was playing. Now she'll sing along with the songs, including the whole of the alphabet song and she recognises some letters and the sounds they make.
My older children also enjoy making words up on my fridge with the letters.
My only critisim is that I would also like a set of lower case letters and some doubles of the most commonly used letters.