Original author:
Kim Igor V. aka KimIV
This spread indicator shows minimum and maximum spread values for the last hour, 4 hours and day. Two additional lines show minimum and maximum spread values on the current bar.
This turned out to be very useful when working with trading account of different brokers.
Originally this indicator has been written in MQL4 and was first published in the Code Base on 6.10.2014.

Fig. 1. The i-Spread indicator