Go to Gunbroker.com and do a search for Bost and you will come up with at least two shotguns like yours that are for sale, and will provide some information on the shotgun itself.
A gauge for measuring magnetism.
A round gauge with a needle to point at the measure.
For wire gauge, 1.25 mm diameter wire is closest to 16 gauge (AWG). See related link.
It is called a rain gauge
gayge gauge gage gaege gaige
Around the 500nzd mark
The proof markings on the gun indicate it was made by Armas Marixa. These shotguns were made in the 1970's. As i find more i will add to this post. Mine is marked Memphis. It is 12 gauge with a three inch chamber.
20 gauge
You can find the value of an Eibar Animo Express 12 gauge shotgun by taking the gun to an expert at a pawn shop or at a gun store. You can also find the value by searching websites like GunStar online.
Spain. Likely pre-Spanish Civil war.
The exact value of a 410 gauge side by side made by Zaballa Hnssbrg Eibar actually depends on a number of things. A couple of these things would be the age and condition of the firearm.
It is likely a 12 gauge, but take it to a gunmith to have it checked.
Not more than $600 if in excellent condition.
try bob's gun shop royal,ar
Union Armera has been making quality guns since the late 1920s. In the 1980s they changed their name to Grulla Armas. They now produce top of the line custom guns. Grulla which means stork, has been their trademark since the companies start. The company is based in Eibar Spain. Depending on the condition of your 205E, I would expect it to be worth between $800 and $2500 USD. I expect the value of these guns to continue to rise.
BOST ARMAS EIBAR SPAIN These Shotguns Are very Rare and are starting to get the attention from serious collectors. Bost shotguns are Manufactured in Eibar Spain and are all hand made. The scroll work on the metal and etching in the wood are done by hand and not stamped. Not to be confused with Boss company of England. There are five gun manufacturer's in the Basque town of Eibar Spain within walking distance of each other. Most of the Bost rifles and shotguns were made and custom fitted for clients who wanted the quality of a hand made rifle pistol or shotgun But didnt want to spend fifty thousand dollars and wait three years as you would for a Boss. A Bost shotgun can range in the range of $200 to $3000 depending on the condition of the gun and the detail of the design. They are a tight gun well built and have the guild stamped of the craftsmen that built it on the barrels,frame or recievers. Some will have the initials of the owner it was commisioned for. Spainish Firearms are not the most desired firearms in the world but they make some nice ones. It depends on your taste. Some people would never own a Reminton or a Belgium made firearm I hope this helped you out a little more. Remember they are very rare here in the U.S
Value as a shooter. Find someone who collects this type and it may bring a small premium.