RAD Peeps. Maxim 38 withMicro Tube Alignment System is the same peep as the Maxim 38, but featuring a modified tubing post. This double tapered alignment post allows the use of a much smaller diameter tubing that increases speed and reduces noise over other tube alignment systems. RAD. Maxim 38 withMicro Tube Alignment System is the same peep as the Maxim 38, but featuring a modified tubing post. Available in these sizes 1/8" & 1/4".