"low-end disruption" which targets customers who do not need the full performance valued by customers at the high-end of the market and "new-market disruption" which targets customers who have needs that were previously unserved by existing incumbents.
"Low-end disruption" occurs when the rate at which products improve exceeds the rate at which customers can adopt the new performance. Therefore, at some point the performance of the product overshoots the needs of certain customer segments. At this point, a disruptive technology may enter the market and provide a product which has lower performance than the incumbent but which exceeds the requirements of certain segments, thereby gaining a foothold in the market.
Relate ReadingClayton M.Christensen