Monster "crochet" hooks

[Addiscomber]

In amongst a mixed lot of knitting needles that I bought on ebay several years ago were the following huge hooks

6.5mm - 34cm long
6mm - 34cm long
5mm - 30cm long
4.5mm - 30cm long (x2)

Can anyone tell me what craft they would used for, please?

[Ellabella]

I think Tunisian crochet uses long hooks.

I think I tried decades ago, it produces a very dense fabric.

[Lilian]

I think Tunisian crochet use double-ended hooks and they are quite long.

[Acorn]

My Tunisian crochet hooks have a hook at one end and a knob (like a knitting needle) on the other, and they are as long as knitting needles.

[Lilian]

You're right @Acorn I can't think what double-ended hooks are used for 

[Addiscomber]

Thanks all. Have never heard of Tunisian crochet before - shall have to Google. I cannot imagine how they are used as they are seriously heavy, but I don't like knitting with anything bigger than about 4.5mm needles and have come to prefer circular needles anyway.

[Kenora]

Tunisian crochet is sort of a cross between crochet and knitting, but it produces a nice, firm fabric and is very easy to do.

[charlotte]

Coming in a bit late to the discussion @Lilian 

You can use a double ended hook for a variation on Tunisian crochet.

Video here.