Max Limit of H1B Extension

[mithu]

HI,

I have question regarding H1-B extension.

I have a question that - "Is there is limit for H1B visa extension" ?

I am on h1-B extension and my extended vis is valid till July 2008.

My Original visa was valid from Oct-2004 to March-2006 (for only 1.5 yrs)

I got extension from March-2006 to July-2008 (For 2.4 yrs)

so its 3.9yrs, and I heard that people on H1B can stay in US for 6 Yrs.

Am I eligible for apply 2nd time H1B extension ?

Thanks.