Spike-MR is/was also known as "Gill" -
http://www.defense-update.com/directory/spike-mr.htm
Spike-LR is now simply called "spike", was also called NTD it seems..
http://www.eschel.co.il/dui/directory/spike-lr.htm
seems the manufacture changed the names? - it's confusing, anyway
ah! - there appear to be 4 variants of Spike, looking at the rafael page:
http://www.rafael.co.il/web/rafnew/products-use.htm
Spike-SR,MR,LR and ER
(I have not looked into the details)
Cheers
Andy