I got tired of the bulky heavy 510.
I am happy to say the M403 is light enough to hold in the kisser with ease.
Even the M401 is pretty light and has good batt life.
BTW the M401/M402/M403 all use the same atty; M403 is very short and the M401 is about the same as a 100mm analog in size.
The M401/M402/M403 experience is pretty close to an analog.
The M401 auto pass
thru is light also.