Abstract　 　　 

　Low luminosity GRBs (llGRBs) are crucial in our understanding of the GRB-SNe connection. Although all SNe accompanying GRBs are similar, llGRBs seem to be very different to those of normal long GRBs in terms of luminosity, rates, and prompt light curves.  Whereas normal long GRBs are originated by a relativistic jet that penetrates the progenitor's envelope, it seems that this is not the case for llGRBs, and a "failed" jet is involved in this case.  There have been several suggestions that llGRBs instead arise when a relativistic shock breaks out from a stellar envelope. In such a case the duration, the energy and the typical peak frequency of the GRB enable us to estimate the conditions during the shock breakout. I will present the expected afterglow signal from this specific scenario and compare it with the observed afterglows of llGRBs.