Ernie Ball guitar strings are exported to 68 countries and are "the world’s favourite guitar strings" (according to Ern!)

The current Slinky range of nickel plated electric guitar strings includes:

2215 - Skinny Top Heavy Bottom 10, 13, 17, 30, 42, 52

2220 - Power Slinky 11, 14, 18p, 28, 38, 48

2221 - Regular Slinky 10, 13, 17, 26, 36, 46

2222 - Hybrid Slinky 09, 11, 16, 26, 36, 46

2223 - Super Slinky 09, 11, 16, 24w, 32, 42

2225 - Extra Slinky 08, 11, 14, 22w, 30, 38

2626 - Not Even Slinky 12, 16, 24p, 32, 44, 56

2627 - Beefy Slinky 11, 15, 22p, 30, 42, 54

The 'p' indicates 'plain' (on the 4th string, which is usually wound)
The 'w' indicates 'wound' (on the 3rd string, which is usually plain)

Unless otherwise stated, guitar strings are usually plain for the 1st, 2nd and 3rd string and wound for the 4th, 5th and 6th string.