Tonearm lift

What's the diff?

Maybe just the shape of the platform that support the armtube, since the arm is linear tracking it's not necessary to make it curved? 

I tried the type to automatically lift the arm at the end of play, like this:

https://www.amazon.com/Audio-Technica-AT6006R-Safety-Raiser/dp/B07HKX6WL7/ref=asc_df_B07HKX6WL7/?tag=hyprod-20&linkCode=df0&hvadid=312094681626&hvpos=1o2&hvnetw=g&hvrand=5472122619530318004&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9002579&hvtargid=pla-576813310257&psc=1

I found out, for short arms, close to the platter, large platter surrounds like the victor tt61,71,81 .., there is not enough space to place it.

If the platter has no wide surround, perhaps it will work for curved, straight, but could a linear arm/cartridge mount trigger it?.

I expect, when I install my 12.5" arm, there will be space to fit one of these.

it arrived from Russia, I will be home late tomorrow, wed am I will know.

Chakster
Eminent Technologies 2.5 linear tracking arm.I'm looking for an auto lift that cues up  at the end of play.

Expressimo  https://elusivedisc.com/expressimo-audio-the-lift-for-all-pivotal-tonearms-except-mmf-pro-ject-rega/ 
I just got one. Works the treat. They go fast and Brian is an aero space machinist. Most of his work is one offs for the military.  He can not make lifts real fast. If none of the stores have them call Brian directly at Expressimo Audio. If you have to wait for Brian to make one you will have to be patient. He also makes custom turntables and a tonearm with a radio controlled VTA ! 
Anyway, the design of this one is brilliant. It puts very little stress on the cantilever and there is no trigger mechanism to get stuck or wear out.

Expressimo, that's the teeter-totter design I was thinking of but couldn't recall the name. Very elegant simple mechanism, you could built it yourself. The trick is its balanced on a lever arm such that the very small sideways force of the arm is enough to tip the balance weight over and send it falling, where then the lower arm comes up and lifts the tone arm. Its a bit sudden and jarring in action but with a little felt in the right places..... also just looking at the pictures you could DIY one pretty easy. With wood for the upright and arm and a bolt screwed into the end turning the bolt would adjust the balance tipping point. It would take a bit of trial and error but nowhere near waiting a week, and cost next to nothing. 

The spring loaded hydraulic lifts are smooth but spendy, and as Mike points out the beauty of the Expressimo is it works on gravity, something that seldom if ever fails to work.