Hex Allen spanner set, OMT², in metric sizes from M3 to M10. This set is compatible with any standard bit holder and/or OMT² handle. The set contains the 6 most commonly used Allen keys. The advantages of this set are that it is compact, easy to store and use. The set is useful in many situations where you may need an Allen key. Keep in mind that this set will never completely replace a set of metal Allen keys, but it can come in handy in some cases.