Along with the HMX Cloud switches, the Swift switches also have an LY stem which is relatively new to HMX. However, the two switches are completely different in almost every other aspect besides stem material and travel distance. The housing materials determined that these two switches differentiate from each other and complement each other.
Design:
The design specs of the Swift switches are pretty similar to the Cloud switches; They both utilized HMX's new MX molding to ensure there is minimum syringe effect which prevents you from having a clean keystroke. The keypress of the Swift switches will not be like pushing down a syringe with air jamming the travel. Also, these switches have a near-full travel distance. However, I do need to clarify that these switches' total travel distance is around 3.9mm despite HMX claiming that they are 4.0mm. There is not much new information to give regarding the structural design of the Swift switches, but the material choices are more than interesting.
Materials:
The stem is still made of LY as described in the specs section. However, the housing of the Swift switches is completely made of new materials that never appeared in any previous HMX switches. The top housing is made of P3 and the bottom housing is made of PA3.0. Let me break those down for you one by one.
The P3 material might sound familiar to some of you as it did for me. JWK had a proprietary blend material called the exact same name. After discussing it with HMX, I learned that the P3 from their material chart is different from the P3 that JWK used. I am not sure what is the composition of the JWK P3, but the HMX P3 material is a modified nylon material with added PTFE to increase its smoothness. They also added some secret sauce to make P3 softer than the other Nylon variants they have. The goal is to create a top housing with a deeper, quieter sound and an even smoother typing feel.
Regarding the bottom housing, it is made of another new modified Nylon material called PA3.0. PA3.0 is similar to PA2 and PA2.0 used by HMX, but the 3.0 is just a bit softer.
As described, we can see that HMX is trying to create softer Nylon variants, and the motivation is that they are trying to create a thocky linear switch. HMX switches are great, but the previous series are all known for their clacky sound signature. In order to make something different and avoid having re-color switches, HMX is experimenting with the Swift switches, and they tried to make it sound thocky. Did they make that happen? I would say yes. Although the Swift switches are as thocky as other famous switches such as the Vertex V1, they are a combination of thock and the signature HMX clack. They have a very satisfying bottom-out sound, and the top-out sound is not going to be sharp like the Hyacinth V2 switches.
As why do I say that the Swift switches and the Cloud switches are brother/sister switches, and they complement each other? It is that the Cloud switches represent the clacky side of the design, and the Swift switches represent the thocky side. No matter your preference for the switch sound, you can choose either of them to experience the smoothness and typing feel that the new molds bring.
Updated HMX Nylon Chart
From most thocky to most Clacky: P3-PA3.0-PA1-PA12-PA2=PA2.0-PA66
Smoothness: They are all very smooth. PA2.0 and PA3.0 are a bit smoother than the rest since they added PTFE to them to increase smoothness and friction resistance.
Switch Type: Linear
Manufacturer: HMX
Stem material: LY
Top Housing: P3
Bottom Housing: PA3.0
Operating Force: 42±5g
Bottom-out Force: 50±5g
Spring: 22mm single-stage spring
Pre-travel: 2.0mm
Total Travel: 3.9±0.3mm (Around 3.7mm in real life)