Devices is a good secondary for most Blasters. However, if you plan on doing any PvP, I'd suggest going with a different secondary powerset - you simply won't have time to use most of the best powers during PvP matches.....unless you're on one of the outdoor maps and its 1v1 or 2v2.

Devices:

Web Grenade - This is the default power, which every Devices blaster has. What it does it does is throw a grenade that explodes into sticky webbing, immobilizing a foe. It can also be used to bring down fliers, if it hits. Only affects one target.

Recommended slotting: 1 accuracy, until you get Targeting Drone. Then replace the accuracy with an immobilize enhancer. I wouldn't recommend more than 2 slots on this power.

Caltrops - Dumps a bunch of small spiked metal pieces in an area which cause minor damage over time and slow the movement of anyone who passes through them. There are a few villain groups with mobs that have this power.

Recommended slotting: 1 range, maybe one recharge as well. Don't bother slotting damage, as it won't be worth it.

Taser - Stuns the target. Unfortunately, you have to be very close to the target to use it. Assault Rifle Blasters can apparently use this and Beanbag to do a pretty good stun that will affect higher level enemies.

Recommended slotting: Unless you're an Assault Rifle Blaster, I'd recommend skipping this. If you do take it, I'd recommend an accuracy enhancer and one or two stun enhancers.

Targeting Drone - THE FIRST MUST HAVE POWER OF THE SET Summons a small drone with red lasers emanating from it that orbits around your head. The drone enhances your accuracy (it only takes ToHit Buff, Recharge and Endurance Reduction enhancers) while activated. This lets you free up a few slots in your primary powerset, using damage or other enhancers in place of accuracy enhancers.

Recommended slotting: All ToHit Buffs. It doesn't use up enough end to bother slotting endurance reduction and has a pretty quick recharge to begin with. Try to get it 4 or 5 slotted with ToHit Buffs. There's no real need to 6 slot it.

Smoke Grenade - Tosses a grenade that causes a cloud of thick black smoke that reduces the accuracy of every mob in the area of effect. Currently, this does not cause aggro and can be used safely if you use this power with some kind of concealment up or from long range. Apparently, this will change in I5, causing aggro when used.

Recommended slotting: Skip it. If you do take it, slot with a couple of ToHit Debuffs. Won't be worth having once I5 goes live if you like to solo unless they don't change it to cause aggro.

Cloaking Device - Basically has the same effect as the Stealth power from the Concealment pool, but with a different visual fx and without the movement penalty. Makes you hard to see and raises your defense even if seen.

Recommended slotting: one endurance reduction and as many defense buff enhancers as you think you can afford.

Note: Depending on how you plan to use your Blaster, you may want to skip this and take the Concealment pool instead: Stealth, Grant Invisibility and Phase Shift. Stealth's movement penalty isn't really noticable when using a travel power and is pretty much a non-factor if you take Swift from the Fitness pool.

Trip Mine THE SECOND MUST HAVE POWER OF THE SET - If you've had trouble soloing up to this point, this power will take care of that problem, although you'll be soloing slowly with this power. Trip Mine drops a mine with red lasers emanating around the edges. Any mob that steps close to the mine triggers it, and the mine does damage and knockback. Can affect more than one target at a time. The recharge is kind of long, but you can lay down several mines. The mines last for around 4 minutes before they self-detonate. I like to stack several mines in one spot rather than lay down a big mine field, unless facing a huge horde of mobs, as the damage from the stacked mines stacks. You can do some major damage with enough mines, although they won't do much to purple con mobs, no matter how many you get down.

Recommended slotting: You'll want to six-slot this power. Either 2 recharges, 4 dmg or 1 recharge, 5 dmg. You'll definitely want one recharge in it.

Time Bomb - Drops a mine that automatically explodes after 15 seconds. Has a larger blast radius and does more damage than a Trip Mine. However, the recharge time is a LOT longer than Trip Mine's. (4 minutes base time as opposed to Trip Mine's base time of 30 seconds) A situational use power, really.

Recommended slotting: 2 recharges, 4 dmg.

Auto turret - Drops a stationary double-barrelled chain gun that fires off about 12 shots (similar to the AR Burst power, but with no defense debuffs) before self-destructing. The good news is, the turret can be targeted, so it can be buffed, healed and teleported around. You'll definitely want to consider getting Recall Friend to go along with this power, if you don't already have it. Comes in handy when you need extra firepower for a few minutes. (I used it a lot when facing AVs or Kronos Class Titans) The Malta group uses this power.

Recommended slotting: 1 accuracy, 5 dmg or 6 dmg.

Munitions Mastery

Note: All Munitions Mastery attacks use the Assault Rifle.

Body Armor - An auto power, meaning its always on. Provides some protection from smashing and lethal damage. The damage resists are being lowered in I5.

Recommended slotting: 2 to 4 damage resists.

Cryo Freeze Ray - Best power of the set, in my opinion Fires a beam of ice that freezes the target in a block of ice, rendering them helpless and doing a small amount of damage over time. This is a great hold - with enough enhancers, you can hold some AVs for a short period of time with it!

Recommended slotting: 1 accuracy, 1 range and 3 or 4 holds.

Sleep Grenade - Fires a grenade that does a small amount of smashing damage and puts targets in the area of effect to sleep for a short period of time. Targets wake up if attacked.

Recommended slotting: I didn't take this power, so what I'm posting is speculation only - 1 recharge and 2 to 4 sleep enhancers.

LRM Missile - Essentially a Sniper Rifle attack that does area effect damage with pretty good knockback. (Has a visible projectile and a missile fire sound effect, but the projectile hits so fast you can barely make it out)

Recommended slotting: 1 range and as many damage enhancers as you can afford. *Maybe* a knockback enhancer, if you like watching several targets get knocked around and can afford to sacrifice some damage.

Devices is a great powerset, and you can pull off some really nasty tricks using some of the powers. (For instance, if you have a hold in your primary set, use it, walk up to the held mob, and drop a Trip Mine - the mine will explode, damaging the mob)

One note of caution I must make: Don't avoid using accuracy in all of your primary powers once you get Targeting Drone; I recommend leaving an accuracy enhancer in your holds and your big attacks such as Nova or Thunderous Blast.