Unfortunately it is out of stock. Inquire as to when it will be in stock, or if pre-ordering is an option. This is the only top rail I would actually trust.
I use this same RAS unit for my SiG552. Haven't had any problems with it at all, and my SiG552 has put up with a lot of bullshit from me. I can't justify suggesting the Proud RAS handguard, same exact item, for $150, when the Allwin handguard has stood the durability test by multiple users and is only 1/3 the price.
Guarder steel bolt. Self explanatory. Although ehobby is international, a steel bolt is not a restricted item. It'll import just fine.
All of these items do not require you to be age verified as they are not restricted items, as well as AirsoftParts does not sell rifles/pistols/firearms of any sort, AirsoftDepot requires you to be age-verified and certified by the site to have access to their restricted items, and ehobby is across oceans, restricted items cannot be imported (Saying this to cover my ass before someone cries about me helping circumvent the AV system since apparently that's the new trend).