If you're looking for a palm tamper instead of a more traditional tamper with a handle, and you're looking for the type you can just push with the palm of your hand, the IKAPE V4 palm tamper is very good quality for the money.
Features and Benefits:
• Calibrated to 30lb of pressure
• Heavy weight (500g/600g/703g depending on the size option)
• 304 stainless steel base
• Aluminium outer shell
• sizes available 51mm/53.3mm/58.5mm
Tamping is one of the shot variables that needs to be locked in place, not changing from shot to shot, while you change one other variable at a time.
For example, you want to be able to just adjust the grind size, and to know that the change in the cup was purely down to the grind adjustment, and it wasn't due to a change in the tamp pressure or a non-level puck.
So having a calibrated tamper that also self levels using the rim of the basket as the guide, is the easiest way to achieve this.
The other option is simply practice, but I've been practising for a good few years now, and whenever I tamp manually, I can still be slightly hit & miss, particular when it comes to tamping completely level, so I do think calibrated self levelling tampers are a good idea.
If you're wanting a calibrated levelling tamper, but you prefer to tamp with the palm of their hand, rather than to grip a traditional tamper with a handle, then a calibrated palm tamper like this may be perfect for you.
The IKAPE products are impressive for the money. Generally speaking they're just slightly lower priced than Normcore, for example, and often there's very little difference in performance, plus some of the IKAPE tools have more interesting looking designs.