I’ll add a little more information.
Ships. There are four distinctive tech levels for ships.
Tech 1: The most basic version. The easiest to train for and use, the cheapest/easiest to build and buy, etc. Can be built by players without needing to train a lot of specialised skills.
Faction. An improved version of a tech 1 ship. Only some tech 1 ships have a faction version. Most tech 1 ships do not have a faction version. More expensive than a tech 1 ship. Some can be built by players but building a faction ship requires a special blueprint that is expensive to get hold of. Some tech 1 ships can be converted into the faction version of that ship using ISK and “loyalty points” with an NPC corporation. Faction ships also include ships from the various “pirate” NPC factions in the game.
Alpha players can train to fly any T1 or faction ship from Frigate to Battleship.
Tech 2: Most tech 1 ships have a tech 2 version, but the tech 2 version of a ship tends to be fairly specialised towards performing a specific role. Tech 2 ships can be built by players but the process of getting blueprints for tech 2 ships and building them is more complicated and expensive compared to building tech 1 ships.
Tech 3: There are two types of tech 3 ships. “tactical destroyers” and “strategic cruisers”. They require specialised skills to fly them but they are designed to be very flexible for the variety of roles they can be used for. Even more expensive and difficult to build than tech 2 ships.
Only Omega players can train to fly tech 2 and tech 3 ships.
Modules follow the same general pattern, with some more levels of items, called “meta level”.
The most basic modules that can be built by players are Tech 1 level . There are also meta levels 1, 2, 3 and 4 which are slightly improved versions of the basic tech 1 item but count as tech 1 for the skill requirements needed to use them. Meta 1, 2, 3 and 4 items cannot be built by players, they are salvaged by players from wrecks of NPC pirate ships.
Tech 2 modules are meta level 5.
Faction modules. These also count as tech 1 for the skills needed to use them, but their meta level starts at 6 and goes up to meta level 8. Some faction modules can drop as loot from wrecks of elite level NPC ships. Some basic Tech 1 modules can be converted to a faction version using ISK and loyalty points with certain NPC corporations and some blueprints for faction modules can be bought from NPC corps.
Officer and Deadspace modules. These modules drop as loot under fairly specific circumstances and are meta level 11 and higher. To the best of my understanding, Officer and Deadspace modules only come in a “large” size for use on battlecruisers and battleships, although they can potentially be used on cruisers, but it’s not so easy to fit them on a cruiser due to how much powergrid and CPU they need from the ship to work. They can be used with the same skill levels needed for Tech 1 modules, but Officer/Deadspace modules are very expensive.
All tech 1, tech 2, faction and Officer/Deaspace modules can be used on basic tech 1 ships. Alpha players cannot use tech 2 battleship sized (large) weapons, but they can use small (frigate & destroyer) and medium (cruiser & battlecruiser) sized tech 2 weapons as well as most other non-weapon tech 2 modules.
Tech 3 modules, only needed for tech 3 strategic cruisers. The tech 3 tactical destroyers do not use the specialised tech 3 modules. There are actually only a small number of tech 3 modules, and they can only be used on tech 3 cruisers. There are specialised skills which must be trained to use each type of tech 3 module.
There are no faction or alternative meta levels for tech 3 modules. Tech 1, faction/officer/deadspace and tech 2 modules can also be used on tech 3 ships, but there is a minimum set of tech 3 modules that MUST be used on a tech 3 cruiser because tech 3 modules are necessary to connect all the other modules to the tech 3 cruiser. You cannot fit other modules to a tech 3 cruiser if the tech 3 cruiser does not have any tech 3 modules attached to it.
Ammunition. Ammunition has three distinct levels. tech 1, faction and tech 2. There is no officer/deadspace or tech 3 ammo. Tech 1 and faction ammo can be used with any weapon system that is appropriate for that ammo, so you can use tech 1 and faction ammo in a tech 2 weapon. Tech 2 ammo can ONLY be used with tech 2 weapons of the correct type. You cannot use tech 2 ammo in a tech 1 or faction weapon.
Tech 1 ammo can be made by players with some basic skills, some basic materials and the right blueprint. Faction ammo is not made by players, it is converted from tech 1 ammo by players through an NPC corp, using ISK and loyalty points. Tech 2 ammo is made by players but requires more advanced skills, more advanced materials and a more advanced blueprint.
Just like tech 2 ships are more specialised in their intended roles compared to tech 1 ships, tech 2 ammunition is also more specialised, and not every type of tech 1 ammo has a tech 2 version, but there are faction versions of every type of tech 1 ammo.